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The photoionization (PI) spectra of small gas-phase yttrium monoxide clusters, YnO (n = 1-8), are investigated, and the adiabatic ionization energies are determined. The stable structures are obtained from density functional theory (DFT) calculations. The ground state structures are further confirmed by the CCSD(T) method. The PI spectra are calculated for these stable structures and are compared with the experimental PI spectra. The ground-state structures of the neutral and cation clusters are experimentally assigned with confidence on the basis of a favourable agreement between the experimental and calculated PI spectra. New structures are proposed for Y2O, Y6O, and Y8O compared to the previous literature. Y2O is a linear molecule in the ground state that was previously proposed as a C2v bent molecule. The YnO clusters become 3-dimensional from n ≥ 3. The O atom stays outside, bridging a triangular face of yttrium clusters. Chemical bonding between the yttrium and oxygen atoms is mostly ionic. The excess charge on the oxygen atom is around 1.4e-, transferred from the yttrium atoms bonded with it. Yttrium atoms are mostly covalently bonded. However, for the bigger clusters, free charges of both polarities appear on yttrium atoms that are not bonded with oxygen, indicating ionic interactions. Frontier orbitals consist of mainly delocalized 4d electrons with some 5s contributions, forming Y-Y bonding interactions, but with little contribution and zero contribution from the oxygen orbitals, regardless of the cluster size. The lost electron of YnO+ mostly comes from the 5s orbitals of all Y atoms in the cluster up to size n = 4, and then from 4d-5s hybrid orbitals from n ≥ 5, with the d contribution increasing with size. This is contrary to the previous view in the literature that photoionization occurs from a localized 4d orbital.
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The study aims to investigate the electronic, optical and phonon dispersion properties of a pure and 2.5% O-defect induced LAGO perovskite, using density functional theory (DFT) with generalized gradient approximation (GGA) and the PBE functional. The research reveals a significant reduction in the band gap from 3.27 eV in pure LAGO to 2.18 eV in defect-induced LAGO. The defect-induced LAGO exhibits relatively strong light absorption in the visible region compared to pure LAGO. The phonon-dispersion analysis identifies one acoustic and two transverse optical mode branches. The calculated Debye temperatures for pure and defect-induced systems are 469.92 K and 463.69 K, respectively, attributed to weaker bonds in defect-induced LAGO. The findings offer fundamental insights into the impact of oxygen vacancies on the electronic, optical, and phonon properties of the LAGO perovskite that can potentially improve the electronic and optoelectronic devices operating across a wide range of spectral frequencies.
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Neutral lanthanum clusters are studied by photoionization time-of-flight mass spectroscopy, laser threshold photoionization spectroscopy, and density functional theory (DFT). Mass abundance spectra (MS) registered at multiple photoionization wavelengths in the range of 195-230 nm by single photon ionization reveal the production of all sizes, Lan (n ≥ 50), in good abundance, nullifying previously predicted low abundances for certain sizes in the 3-14 size range. Also, the MS do not reveal the extraordinary stability of any specific size, as one would expect, from previous theoretical predictions of 7- and 13-atom clusters as magic. Ionization energies (IEs) are measured for Lan (n = 2-14) clusters. DFT has been used to determine the stable geometric isomers for 2- to 10-atom clusters and to calculate their IEs. The theoretical IEs of 2-7 atom clusters are in decent agreement with their experimental values; however, the theoretical IEs are somewhat lower by â¼0.4 eV for n ≥ 8 than their experimental IEs.
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Antimicrobial resistance is an ever-increasing problem throughout the world and has already reached severe proportions. Two very common neglected tropical diseases are Chagas' disease and leishmaniasis. Chagas' disease is a severe health problem, mainly in Latin America, causing approximately 50000 deaths a year and millions of people are infected. About 25-30% of the patients infected with Trypanosoma cruzi develop the chronic form of the disease. On the other hand, Leishmaniasis represents complex diseases with an important clinical and epidemiological diversity. It is endemic in 88 countries 72 of which are developing countries and it has been estimated that are 12 million people infected and 350 million are in areas with infection risk. On this basis, research on organic compounds that can be used against these two diseases is an important target. A very simple, green, and efficient protocol is developed in which bismuth nitrate pentahydrate is employed as a Lewis acid catalyst in aqueous media under microwave irradiation for the synthesis of various 2-aryl substituted benzimidazoles from aldehydes and o-phenylenediamine. Other salient features of this protocol include milder conditions, atom-economy, easy extraction, and no wastes. Nine 1H-benzimidazole derivatives (1-9) with substituents at positions 2 and 5 were synthesized and the structure of the compounds was elucidated by spectroscopic methods. The compounds were screened to identify whether they posses pharmacological activity against Chagas' disease and leishmaniasis. Compound 8 showed better activity than the control Nifurtimox against INC-5 Trypanosoma cruzi strain whereas compounds 3 and 9 have demonstrated potent leshmanicidal activity. A systematic green synthetic procedure and in vitro biological evaluation of nine 1H-benzimidazoles are described.
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Antiprotozoarios/farmacología , Bencimidazoles/farmacología , Anfotericina B/farmacología , Antiprotozoarios/síntesis química , Antiprotozoarios/química , Bencimidazoles/síntesis química , Bencimidazoles/química , Enfermedad de Chagas/tratamiento farmacológico , Tecnología Química Verde , Calefacción , Leishmania mexicana/efectos de los fármacos , Leishmaniasis/tratamiento farmacológico , Microondas , Nifurtimox/farmacología , Nitroimidazoles/farmacología , Trypanosoma cruzi/efectos de los fármacosRESUMEN
The present study reports transition metal (TM = Cr, Mn and Fe) doped silicon nanotubes with tunable band structures and magnetic properties by careful selection of cluster assemblies as building blocks using the first-principles density functional theory. We found that the transition metal doping and in addition, the hydrogen termination process can stabilize the pure silicon nanoclusters or cluster assemblies and then it could be extended as magnetic nanotubes with finite magnetic moments. Study of the band structures and density of states (DOS) of different empty and TM doped nanotubes (Type 1 to Type 4) show that these nanotubes are useful as metals, semiconductors, semi-metals and half-metals. These designer magnetic materials could be useful in spintronics and magnetic devices of nanoscale order.
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The present study reports the geometry, electronic structure, growth behavior and stability of neutral and ionized nickel encapsulated germanium clusters containing 1-20 germanium atoms within the framework of a linear combination of atomic orbital density functional theory (DFT) under a spin polarized generalized gradient approximation. In the growth pattern, Ni-capped Gen and Ni-encapsulated Gen clusters appear mostly as theoretical ground state at a particular size. To explain the relative stability of the ground state clusters, variation of different parameters, such as average binding energy per atom (BE), embedding energy (EE) and fragmentation energy (FE) of the clusters, were studied together with the size of the cluster. To explain the chemical stability of the clusters, different parameters, e.g., energy gap between the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO gap), ionization energy (IP), electron affinity (EA), chemical potential (µ), chemical hardness (η), and polarizability etc. were calculated and are discussed. Finally, natural bond orbital (NBO) analysis was applied to understand the electron counting rule applied in the most stable Ge10Ni cluster. The importance of the calculated results in the design of Ge-based superatoms is discussed.
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The present study reports the geometries, electronic structures, growth behavior, and stabilities of neutral and ionized copper-doped germanium clusters containing 1-20 Ge atoms within the framework of linear combination of atomic orbitals density functional theory (DFT) under the spin-polarized generalized gradient approximation. It was found that Cu-capped Ge(n) (or Cu-substituted Ge( n+1)) and Cu-encapsulated Ge(n) clusters mostly occur in the ground state at a particular cluster size (n). In order to explain the relative stabilities of the ground-state clusters, parameters such as the average binding energy per atom (BE), the embedding energy (EE), and the fragmentation energy (FE) of the clusters were calculated, and the resulting values are discussed. To explain the chemical stabilities of the clusters, parameters such as the energy gap between the highest occupied and the lowest unoccupied molecular orbitals (the HOMO-LUMO gap), the ionization energy (IP), the electron affinity (EA), the chemical potential (µ), the chemical hardness (η), and the polarizability were calculated, and the resulting values are also discussed. Natural atomic orbital (NAO) and natural bond orbital (NBO) analyses were also used to determine the electron-counting rule that should be applied to the most stable Ge(10)Cu cluster. Finally, the relevance of the calculated results to the design of Ge-based superatoms is discussed.
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Simulación por Computador , Complejos de Coordinación/química , Cobre/química , Germanio/química , Modelos Moleculares , Algoritmos , Conformación Molecular , Teoría Cuántica , TermodinámicaRESUMEN
The present study reports the effect of oxygen addition on small size Ni(n) (n = 1-6) clusters in different spin states within the framework of linear combination of atomic orbital (LCAO) density functional theory (DFT) under spin polarized generalized gradient approximation (GGA) functional. Relative stabilities of the optimized clusters are discussed on the basis of the calculated parameters, such as, binding energy (BE), embedding energy (EE) and fragmentation energy (FE). Other parameters, like ionization potential (IP), electron affinity (EA), etc. show that though the additions of oxygen can affect the chemical properties of Ni(n) clusters with an additional stability to Ni(n)O. In most of the cases the magnetic moment of the stable isomers are geometry dependent for a particular size both in pure and oxidized clusters. Calculated magnetic moments of Ni(n)O (n = 1-6) clusters reveal that the magnetic moment of ground state Ni(4)O isomers in different geometries is same as in pure Ni(4) isomers. Present study also explains the cause of stable magnetic moment in Ni(4)O cluster through the distribution of electrons in different orbitals.
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Electrones , Imanes , Níquel/química , Oxígeno/química , Modelos QuímicosRESUMEN
The present study reports the geometry, electronic structure and properties of neutral and anionic transition metal (TM = Ti, Zr and Hf)) doped germanium clusters containing 1 to 20 germanium atoms within the framework of linear combination of atomic orbitals density functional theory under spin polarized generalized gradient approximation. Different parameters, like, binding energy (BE), embedding energy (EE), energy gap between the highest occupied and lowest unoccupied molecular orbitals (HOMO-LUMO), ionization energy (IP), electron affinity (EA), chemical potential etc. of the energetically stable clusters (ground state cluster) in each size are calculated. From the variation of these parameters with the size of the clusters the most stable cluster within the range of calculation is identified. It is found that the clusters having 20 valence electrons turn out to be relatively more stable in both the neutral and the anionic series. The sharp drop in IP as the valence electron count increases from 20 to 21 in neutral cluster is in agreement with predictions of shell models. To study the vibrational nature of the clusters, IR and Raman spectrum of some selected TM@Ge(n) (n = 15,16,17) clusters are also calculated and compared. In the end, relevance of calculated results to the design of Ge-based super-atoms is discussed.
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Germanio/química , Hafnio/química , Titanio/química , Circonio/química , Simulación por Computador , Electrones , Modelos Químicos , Modelos Moleculares , Estructura Molecular , Teoría CuánticaRESUMEN
The relative stability of Sc, Ti, and V encapsulating Ge(n) clusters in the size range n = 14-20 has been studied through first-principles electronic structure calculations based on density functional theory. Variations of the embedding energy, gap between the highest occupied and the lowest occupied molecular orbitals, ionization potential, vertical detachment energy, and electron affinity with cluster size have been calculated to identify clusters with enhanced stability. The enhanced stability of some clusters can be very well explained as due to the formation of a filled shell free-electron gas inside the Ge cages. For the first time, direct evidence of the formation of a free-electron gas is also presented. In some other clusters, enhanced stability is found to originate from geometric effects. Some clusters that may be expected to have enhanced stability from simple electron counting rules do not show that. These results provide new insights into the long-standing question of whether electron counting rules can explain the relative stability of transition metal encapsulated semiconductor clusters and show that these clusters are too complex for such simple generalizations.
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Structure and electronic properties of neutral and cationic pure and Ni-doped Ge clusters containing 1-20 Ge atoms are calculated within the framework of linear combination of atomic orbitals density functional theory. It is found that in clusters containing more than 8 Ge atoms the Ni atom is absorbed endohedrally in the Ge cage. Relative stability of Ni-doped clusters at different sizes is studied by calculating their binding energy, embedding energy of a Ni atom in a Ge cluster, highest-occupied molecular orbital to lowest-unoccupied molecular orbital gap, and the second-order energy difference. Clusters having 20 valence electrons turn out to be relatively more stable in both the neutral and the cationic series. There is, infact, a sharp drop in IP as the valence electron count increases from 20 to 21, in agreement with predictions of shell models. Relevance of these results to the designing of Ge-based superatoms is discussed.
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In this paper we present an ab initio electronic-structure calculation performed using density functional theory (DFT) with a polarized basis set (SDD) within the spin polarized generalized gradient approximation for pure and divalent transition metal doped hydrogenated germanium nanocluster cages Ge(n)H(n)M (M = Zn, Cd and Hg, n = 6-28). In the first step of the calculation, geometrical optimizations of the nanoclusters are done. In the next step only the ground state optimized geometries are used to calculate the binding energy (E(b)), HOMO-LUMO gap (Delta E(g)) and embedding energy of the clusters. To study the optical behaviour of the clusters, IR and Raman spectra are calculated. Further calculations on cation and anion clusters have been done only for pure and Zn doped clusters to obtain their vertical ionization potential (VIP), adiabatic electron affinity (AEA) and chemical potential.
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Germanio/química , Nanoestructuras/química , Cadmio/química , Electroquímica , Hidrógeno/química , Mercurio/química , Modelos Químicos , Modelos Moleculares , Espectrometría Raman , Termodinámica , Zinc/químicaRESUMEN
AIM OF THE STUDY: Cajanus cajan Linn. (Leguminosae) is a nontoxic edible herb, widely used in Indian folk medicine for the prevention of various liver disorders. In the present study we have demonstrated that methanol-aqueous fraction (MAF2) of Cajanus cajan leaf extract could prevent the chronically treated alcohol induced rat liver damage. MATERIALS AND METHODS: Chronic doses of alcohol (3.7 g/ kg) orally administered to rats for 28 days and liver function marker enzymes such as GPT, GOT, ALP and anti-oxidant enzyme activities were determined. Effect of MAF2 at a dose of 50mg/kg body weight on alcohol treated rats was noted. RESULTS: Alcohol effected significant increase in liver marker enzyme activities and reduced the activities of anti-oxidant enzymes. Co-administration of MAF2 reversed the liver damage due to alcohol; it decreased the activities of liver marker enzymes and augmented antioxidant enzyme activities. We also demonstrate significant decrease of the phase II detoxifying enzyme, UDP-glucuronosyl transferase (UGT) activity along with a three- and two-fold decrease of UGT2B gene and protein expression respectively. MAF2 co-administration normalized UGT activity and revived the expression of UGT2B with a concomitant expression and nuclear translocation of Nrf2, a transcription factor that regulates the expression of many cytoprotective genes. CONCLUSION: Cajanus cajan extract therefore shows a promise in therapeutic use in alcohol induced liver dysfunction.
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Cajanus , Citoprotección , Hígado/efectos de los fármacos , Extractos Vegetales/farmacología , Fosfatasa Alcalina/metabolismo , Animales , Etanol/toxicidad , Glucuronosiltransferasa/genética , Masculino , Factor 2 Relacionado con NF-E2/metabolismo , Estrés Oxidativo/efectos de los fármacos , Hojas de la Planta/química , Ratas , Ratas Sprague-DawleyRESUMEN
To understand the mechanism of cardiovascular dysfunction in the hyperthyroid condition, the role of oxidative stress was examined in rats treated with 3,5,3'-triiodo-l-thyronine (T3). Treatment of rats daily with T3 (8 microg/100 g BW) for 15 days resulted in an increase in heart weight to body weight ratio, which was ameliorated by antioxidants, melatonin (2 mg/100 g BW) or vitamin E (4 mg/100 g BW). Both melatonin and vitamin E also inhibited rises of lipid peroxidation and hydroxyl radical generation and prevented the inhibition of Cu,Zn-superoxide dismutase in the hypertrophic heart. The expression of the glucose transporter, GLUT4, was reduced in response to T3, which was completely restored by melatonin and partially by vitamin E. However, neither antioxidant prevented down regulation of peroxisome proliferator-activated receptor-alpha in the hyperthyroid heart. Furthermore, the reduced level of myocyte enhancer factor-2, a regulator of GLUT4 transcription was restored completely by melatonin and partially by vitamin E treatment. Glucose uptake in hypertrophic left ventricular cells was also restored by these antioxidants. The expression of B-type natriuretic peptide, a marker of heart failure, was significantly increased by T3 and ameliorated by melatonin or vitamin E treatments. In general, the beneficial effects of melatonin given as a co-treatment with T3 were better than those induced by vitamin E. These data show that melatonin ameliorates hypertrophic growth of the myocardium induced by hyperthyroidism and provide an insight into the mechanism of reactive oxygen species-mediated down regulation of metabolically important genes such as GLUT4 in the heart.
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Cardiomiopatía Dilatada/fisiopatología , Transportador de Glucosa de Tipo 4/fisiología , Hipertiroidismo/fisiopatología , Melatonina/fisiología , Estrés Oxidativo/fisiología , Animales , Radicales Libres/metabolismo , Expresión Génica , Glucosa/metabolismo , Masculino , Miocitos Cardíacos/metabolismo , Factores Reguladores Miogénicos/fisiología , Ratas , Ratas Sprague-Dawley , Superóxido Dismutasa/metabolismo , Vitamina E/fisiologíaRESUMEN
Availability of genome sequences of pathogens has provided a tremendous amount of information that can be useful in drug target and vaccine target identification. One of the recently adopted strategies is based on a subtractive genomics approach, in which the subtraction dataset between the host and pathogen genome provides information for a set of genes that are likely to be essential to the pathogen but absent in the host. This approach has been used successfully in recent times to identify essential genes in Pseudomonas aeruginosa. We have used the same methodology to analyse the whole genome sequence of the human gastric pathogen Helicobacter pylori. Our analysis revealed that out of the 1590 coding sequences of the pathogen, 40 represent essential genes that have no human homolog. We have further analysed these 40 genes by the protein sequence databases to list some 10 genes whose products are possibly exposed on the pathogen surface. This preliminary work reported here identifies a small subset of the Helicobacter proteome that might be investigated further for identifying potential drug and vaccine targets in this pathogen.
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Genoma Bacteriano , Infecciones por Helicobacter/tratamiento farmacológico , Helicobacter pylori/genética , Antibacterianos/uso terapéutico , Proteínas Bacterianas/genética , Biología Computacional , Bases de Datos de Proteínas , Helicobacter pylori/patogenicidad , HumanosRESUMEN
Gastric hyperacidity and ulceration of the stomach mucosa due to various factors are serious health problems of global concern. Although the mechanism of acid secretion from the parietal cells is now well understood, the processes involved in gastric ulceration are still not clear. Among the various causes of gastric ulceration, lesions caused by stress, alcohol consumption, Helicobacter pylori and due to use of non-steroidal anti-inflammatory drugs have been shown to be mediated largely through the generation of reactive oxygen species, especially the hydroxyl radical. A number of excellent drugs, developed over the decades, have proven useful in controlling hyperacidity and ulceration although their long-term use is reported to be associated with various side effects. Hence the investigations continue with an objective to find a compound possessing anti-secretory, anti-ulcer and antioxidant properties which will serve as a therapeutic agent to reduce gastric hyperacidity and ulcers. This article describes the role of reactive oxygen species in gastric ulceration, briefly presents a note on the currently available drugs controlling them, and focuses on the role of melatonin, a pineal secretory product, in protecting against gastric lesions. In experimental studies, melatonin has been shown to be effective in reducing mucosal breakdown and ulcer formation in a wide variety of situations. Additionally, the low toxicity of melatonin supports further investigation of this molecule as a promising gastro-protective agent. Finally, we include a commentary on how melatonin research with respect to gastric pathophysiology can move forward with a view to eventually using this indole as a therapeutic agent alone or in combination with the existing drugs to control gastric ulceration in humans in order to increase their efficacy and/or to reduce their side effects.
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Melatonina/metabolismo , Especies Reactivas de Oxígeno/metabolismo , Úlcera Gástrica/tratamiento farmacológico , Úlcera Gástrica/metabolismo , Animales , Antiulcerosos/química , Antiulcerosos/uso terapéutico , Jugo Gástrico/metabolismo , Humanos , Úlcera Gástrica/inducido químicamente , Úlcera Gástrica/patología , Estrés FisiológicoRESUMEN
Ischemic heart disease (IHD) has now assumed a global dimension. It still remains one of the major health problems not only in the advanced countries, but also, is becoming a serious health issue in the developing and the economically weaker countries. Apart from other factors, changing economic scenario, stress and strain in daily life as well as altered dietary habits in the populations appear responsible for the increased incidence of cardiovascular disease (CVD). The treatment modalities, invasive, non-invasive and pharmacological are economically no dearer, even to population of affluent countries. Likewise, treatment costs of serious cardiovascular diseases are becoming difficult to be borne by population of the developing nations. Prevention of IHD would be a better way to protect the population from physical and economic disaster. The current article comprehensively describes the relation between oxidative stress and cardiac disease, explains the direct effect of reactive oxygen species on cardiac function and projects how the use of vitamin E can be of benefit in the prevention of IHD with concluding remarks highlighting the need for inclusion of a fruit and vegetable rich diet and regular exercise to keep the dearer heart active and healthy.
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Antioxidantes/uso terapéutico , Isquemia Miocárdica/prevención & control , Vitamina E/uso terapéutico , Animales , Antioxidantes/efectos adversos , Humanos , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Vitamina E/efectos adversosRESUMEN
The antiulcer effect of melatonin on gastric lesions caused by piroxicam was studied with the intent of determining the mechanism of action of this agent. Melatonin dose-dependently lowered piroxicam and indomethacin-induced gastric damage with more than 90% inhibition at a dose of 60 mg/kg BW. Increased lipid peroxidation, augmented protein oxidation and decreased glutathione content of the gastric tissue following piroxicam treatment indicated a possible involvement of oxidative stress in this nonsteroidal anti-inflammatory drug (NSAID)-induced gastropathy. Pretreatment of rats with melatonin prevented these changes. Oral administration of piroxicam to rats caused a threefold increase in the tissue levels of hydroxyl radical generation, a change significantly attenuated by melatonin. Furthermore, a decrease in the activity of gastric peroxidase and an increase in the activity of gastric superoxide dismutase(s) (SOD) because of piroxicam treatment was attenuated by melatonin pretreatment indicating that the indole possibly exerts its gastroprotective effects through its direct as well as indirect antioxidant activities. The results of the present studies also reveal that melatonin may influence the expression of Cu-Zn SOD, catalase, cyclooxygenase as well as alpha-actinin whose levels were found to be altered, following piroxicam treatment. The current studies, therefore, document melatonin's gastroprotective ability against piroxicam-induced gastric damage and the findings raise the possibility of melatonin being considered as a co-therapy with piroxicam or other NSAIDs in reducing the gastropathy when long-term use of these nonsteroidal agents are unavoidable.
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Antiinflamatorios no Esteroideos/efectos adversos , Melatonina/farmacología , Piroxicam/efectos adversos , Úlcera Gástrica/prevención & control , Actinina/efectos de los fármacos , Actinina/metabolismo , Animales , Antiulcerosos/farmacología , Catalasa/efectos de los fármacos , Catalasa/metabolismo , Ciclooxigenasa 1 , Inhibidores de la Ciclooxigenasa/farmacología , Relación Dosis-Respuesta a Droga , Depuradores de Radicales Libres/farmacología , Mucosa Gástrica/efectos de los fármacos , Mucosa Gástrica/metabolismo , Radical Hidroxilo/metabolismo , Isoenzimas/efectos de los fármacos , Isoenzimas/metabolismo , Peroxidación de Lípido/efectos de los fármacos , Proteínas de la Membrana , Peroxidasas/efectos de los fármacos , Peroxidasas/metabolismo , Prostaglandina-Endoperóxido Sintasas/efectos de los fármacos , Prostaglandina-Endoperóxido Sintasas/metabolismo , Ratas , Ratas Wistar , Úlcera Gástrica/inducido químicamente , Superóxido Dismutasa/efectos de los fármacos , Superóxido Dismutasa/metabolismoRESUMEN
Heart disease is one of the major health problems of advanced as well as developing countries of the world. Extensive research through the last decade has shown beyond doubt that free radicals, particularly, reactive oxygen species play a cardinal role in the pathogenesis of oxidative myocardial damage with consequential cardiac malfunction. This review presents a comprehensive account of the present day knowledge regarding the oxygen free radicals involved in the genesis of ischemic heart disease, the mechanism(s) of oxidative myocardial damage and the endogenous as well as exogenous antioxidant defense systems. Furthermore, the role of ischemic pre-conditioning, some antioxidants and the ability of some cardioprotective drugs in providing protection against the ischemic myocardial damage are also discussed. The text of the article comes to an end with a commentary on the future research perspective in the concerned area, which throws a light on the development of combinatorial therapeutics in the treatment of ischemic myocardial disease.
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Antioxidantes/uso terapéutico , Cardiotónicos/uso terapéutico , Isquemia Miocárdica/etiología , Estrés Oxidativo , Animales , Antioxidantes/fisiología , Cardiotónicos/química , Radicales Libres/metabolismo , Humanos , Precondicionamiento Isquémico , Estructura Molecular , Isquemia Miocárdica/tratamiento farmacológico , Isquemia Miocárdica/prevención & control , Daño por Reperfusión Miocárdica/tratamiento farmacológico , Daño por Reperfusión Miocárdica/prevención & control , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Administration of isoproterenol to mice at a dose of 30 mg/100 g body weight for 3 consecutive days at an interval of 24 h induced lipid peroxidation in cardiac tissue and exhibited a significantly elevated serum glutamate oxaloacetate transaminase (SGOT) level. Increased superoxide dismutase (SOD) activity with a concomitant decrease in catalase activity has also been observed in cardiac tissue with isoproterenol treatment. Quinidine, a class I antiarrhythmic agent has been found to exhibit a protective role in isoproterenol induced myocardial ischaemia. Cardiac tissue of quinidine treated mice showed reduction of lipid peroxidation reaction. In addition, quinidine treatment is found to influence the cardiac antioxidant enzymes - catalase and SOD. The decrease of SOD activity and increase of catalase activity suggests that quinidine also exerts an 'indirect antioxidant' effect in protecting the myocardial tissue from reactive oxygen species. Furthermore, our current in vitro studies with quinidine have clearly shown in this work that it possesses a very convincing hydroxyl radical scavenging potential with almost no ability to scavenge superoxide anion and hydrogen peroxide (H2O2) in vitro. Thus, our present investigation suggests that quinidine, when administered to mice, strengthens the antioxidant defense system to resist the free radical induced damage brought about by isoproterenol induced ischaemic condition.