[show abstract][hide abstract] ABSTRACT: Mucuna pruriens has been used by native Nigerians as a prophylactic for snakebite. The protective effects of M. pruriens seed extract (MPE) were investigated against the pharmacological actions of N. sputatrix (Javan spitting cobra) venom in rats. The results showed that MPE-pretreatment protected against cardiorespiratory and, to a lesser extent, neuromuscular depressant effects of N. sputatrix venom. These may be explained at least in part by the neutralisation of the cobra venom toxins by anti-MPE antibodies elicited by the MPE pretreatment.
Indian journal of experimental biology 04/2011; 49(4):254-9. · 1.20 Impact Factor
[show abstract][hide abstract] ABSTRACT: The seed, leaf and root of Mucuna pruriens have been used in traditional medicine for treatments of various diseases. In Nigeria, the seed is used as oral prophylactics for snakebite.
To study the protective effects of Mucuna pruriens seed extract against the lethalities of various snake venoms.
Rats were pre-treated with Mucuna pruriens seed extract and challenged with various snake venoms. The effectiveness of anti-Mucuna pruriens (anti-MPE) antibody to neutralize the lethalities of snake venoms was investigated by in vitro neutralization.
In rats, MPE pre-treatment conferred effective protection against lethality of Naja sputatrix venom and moderate protection against Calloselasma rhodostoma venom. Indirect ELISA and immunoblotting studies showed that there were extensive cross-reactions between anti-MPE IgG and venoms from many different genera of poisonous snakes, suggesting the involvement of immunological neutralization in the protective effect of MPE pre-treatment against snake venom poisoning. In vitro neutralization experiments showed that the anti-MPE antibodies effectively neutralized the lethalities of Asiatic cobra (Naja) venoms, but were not very effective against other venoms tested.
The anti-MPE antibodies could be used in the antiserum therapy of Asiatic cobra (Naja) bites.
Journal of ethnopharmacology 07/2009; 123(2):356-8. · 2.32 Impact Factor
[show abstract][hide abstract] ABSTRACT: We investigated the mechanism of action of uricase, which oxidizes uric acid to allantoin, in the rat. Allantoin may decompose chemically to urea and hydantoin, containing the carbons in positions 2 and 8 of the purine ring, respectively. These carbons are derived by formylation, catalyzed by formyltransferase, in two reactions of de novo synthesis. Since uric acid and allantoin are represented in equivalent amounts in the liver, we expected to find identical incorporation of radioactivity in C(2) and C(8) of both compounds after administration of (14)C-formate. In the case of (14)C-allantoin, this was true, but not for (14)C-uric acid extracted from rat liver. We interpret these results through a series of experiments and considerations.
[show abstract][hide abstract] ABSTRACT: B-CLL is the most frequent type of leukemia in the Western countries. The disease, common among the elderly, follows a variable course in terms of survival time and symptoms. There is evidence that the accumulation of lymphocytes in peripheral blood and bone marrow is due to a cell resistance to apoptosis rather than to highly proliferative cells. Genetic mechanisms that lead to the development and progression of disease are mainly unknown, although a number of prognostically and diagnostically important genetic markers have been identified. The aim of this study is to investigate the gene expression profile, by a specific chip for microarray analysis, in B-CLL lymphocytes with regard to factors involved in apoptosis cascade, signal transduction, purine metabolism enzymes, interleukin expression, enzymes involved in the responses to oxidative stress. We found relevant results in a set of 19 of the 57 genes considered. IMP dehydrogenase, adenine phosphoribosyltransferase, adenylosuccinate lyase, adenylate kinase, ADORA1, G-protein-coupled receptor kinase 6, Bcl-2-like 1 isoform 2, caspase 6, and 8 were found underexpressed; while ADORA3, Gars-Airs-Gart, adenylate kinase 3, adenylate deaminase, NMN adenylyltransferase, CD26, CD38, interleukins 18 and 4 were found overexpressed. The microarray technique is a powerful method for identification of potential important diagnostic and prognostic markers, besides giving prominence to genes candidate for further studies.
[show abstract][hide abstract] ABSTRACT: Crude rat liver extract showed AMP-AMP phosphotransferase activity which, on purification, was ascribed to a novel interaction between adenylate kinase, also known as myokinase (EC 18.104.22.168), and adenosine kinase (EC 22.214.171.124). The activity was duplicated using the same enzymes purified from recombinant sources. The reaction requires physical contact between myokinase and adenosine kinase, and the net reaction is aided by the presence of adenosine deaminase (EC 126.96.36.199), which fills the gap in the energy balance of the phosphoryl transfer and shifts the equilibrium towards ADP and inosine synthesis. The proposed mechanism involves the association of adenosine kinase and myokinase through non-covalent, transient interactions that induce slight conformational changes in the active site of myokinase, bringing two already bound molecules of AMP together for phosphoryl transfer to form ADP. The proposed mechanism suggests a physiological role for the enzymes and for the AMP-AMP phosphotransferase reaction under conditions of extreme energy drain (such as hypoxia or temporary anoxia, as in cancer tissues) when the enzymes cannot display their conventional activity because of substrate deficiency.
[show abstract][hide abstract] ABSTRACT: Free radical excess and oxidative stress are implicated in the formation and progression of atherosclerotic plaque through actions on susceptible vascular cells, such as by activating xanthine oxidase. Purine bases and other antioxidant compounds could play important protective roles in atherogenesis, as could nonenzymatic low molecular weight thiol defenses, not previously evaluated in carotid artery plaque. Therefore, we measured purine catabolites (hypoxanthine, xanthine, uric acid, allantoin) and antioxidant compounds (total sulphydryl groups, homocysteine, cysteine, and glutathione) in advanced carotid artery plaque and found a high ratio of allantoin to uric acid, suggesting a ongoing local oxidative stress.
[show abstract][hide abstract] ABSTRACT: Nitric oxide (NO), an unstable derived of nitrogen, is released by endothelium in response to physiological stimulus. Indeed, the endothelium is not only a barrier between the lumen and the inner side of the vessel wall but also a metabolically active organ with endocrine, paracrine and autocrine functions. Endothelial vascular cells play an important role in the regulating vasomotor tone, local homeostasis and vascular bed proliferation. NO mediates the vasodilation and inhibits platelet aggregation, expression of molecular adhesion of monocyte, neutrophils adhesion and smooth muscle growth. Atherosclerosis risk factors such as hypercholesteremia, high blood pressure, smoking and oxidative stress inhibit NO production, leading paradoxically to vasodilatation, which affects endothelial function and may lead to ischemic manifestations in patients with arterial pathology. Therapies that increase NO production may improve endothelial vasodilatation. To check whether a decrease or lower production of NO terminates with the initial formation of atheromatous plaque or whether it continues, we determined the content of NO in plasma and plaque of subjects undergoing carotid surgery and in plasma of control subjects.
[show abstract][hide abstract] ABSTRACT: Adenosine kinase is an enzyme catalyzing the reaction: adenosine + ATP --> AMP + ADP. We studied some biochemical properties not hitherto investigated and demonstrated that the reaction can be easily reversed when coupled with adenosine deaminase, which transforms adenosine into inosine and ammonia. The overall reaction is: AMP + ADP --> ATP + inosine + NH(3). The exoergonic ADA reaction shifts the equilibrium and fills the energy gap necessary for synthesis of ATP. This reaction could be used by cells under particular conditions of energy deficiency and, together with myokinase activity, may help to restore physiological ATP levels.
[show abstract][hide abstract] ABSTRACT: Previously, we reported the antisnake venom properties of a Mucuna pruriens seed extract (MPE) and tested its in vivo efficacy against Echis carinatus venom (EV) in short- (1 injection) and long-term (three weekly injections) treatments. The aim of the present study was to investigate plasma proteome changes associated with MPE treatments and identify proteins responsible for survival of envenomated mice (CHALLENGED mice). Six treatment groups were studied. Three control groups: one saline, one short-term and one long-term MPE treatment. One group received EV alone. Two test groups received EV with either a short-term or long-term MPE treatment (CHALLENGED mice). The plasma from each group was analysed by 2-DE/MALDI-TOF MS. The most significant changes with treatment were: albumin, haptoglobin, fibrinogen, serum amyloid A and serum amyloid P. Most of these changes were explained by EV effects on coagulation, inflammation and haemolysis. However, MPE treatments prevented the EV-induced elevation in HPT. Consequently, HPT levels were similar to controls in the plasma of CHALLENGED mice. The plasma of CHALLENGED mice showed substantial proteomic modifications. This suggests the mechanism of MPE protection involves the activation of counterbalancing processes to compensate for the imbalances caused by EV.
[show abstract][hide abstract] ABSTRACT: Organ dysfunction secondary to ischemia-reperfusion (I/R) injury still represents a major problem in liver transplantation. Apoptosis has been observed in hepatocytes and sinusoidal endothelial cell, following I/R injury and it has been postulated as a contributing factor in ischemia-reperfusion graft dysfunction, involving a complex series of events, as changes of protein tyrosine-kinase phosphorylation. We evaluated hepatic purine metabolites, protein tyrosine phosphatases (PTPs), nitrate plus nitrite levels (NOx), caspase-3 (C-3) activity and DNA fragmentation in the time course of twelve pig orthotopic liver transplantation. Biopsies were taken before explantation (t0), after cold ischemic storage (t1) and 30 min from reperfusion (t2). During the ischemic period we observed a reduction of high energy phosphates and an increase of purine bases; PTP activity was largely increased. At t2 high energy phosphates showed a tendency to increase with respect to t1, with a partial restoration of phosphorylation potential, measured as ATP/ADT ratio. PTP activity was significantly reduced, with a concomitant increase of NOx production and C-3 activity; in a considerable number of cases we observed a sustained DNA fragmentation. We speculate that NOx production could be related to nitrosative stress, which in turn leads to dynamic alteration in PTP balance and cell signalling, regulating the activity of a number of proteins implicated in apoptotic cell death. These findings could be of interest in new potential strategy to prevent and treat I/R injury.
[show abstract][hide abstract] ABSTRACT: Many studies have pointed out a possible role of gut peptides, including gastrin and ghrelin, in the pathogenesis and natural history of gastrointestinal malignancies, one of the most common death cause in the Western world. The objective of this work is to check gastrin and ghrelin serum levels in patients with colorectal cancer according to tumour's location, stage, Helicobacter pylori infection and BMI, in order to understand the two peptides' behaviour through the tumour's natural history and evaluate their assay's use in research and clinical practice. Twenty-nine subjects affected by colorectal cancer and 50 healthy controls were studied. Circulating gastrin and ghrelin levels and H. pylori serum antibodies were assessed by radioimmunologic assay and ELISA method. Gastrin and ghrelin serum levels were respectively slightly higher and significantly lower in colon cancer patients than in controls. Gastrin levels were higher in patients carrying left colon cancer and H. pylori infection while ghrelin levels were lower in both these groups. Both hormones' serum levels decreased from tumour earlier to later stages. Significant differences persisted in the correlation between BMI and ghrelin levels in controls but not in patients. Additional studies are necessary to ascertain the significance of gastrin and ghrelin opposite behaviour in colon cancer probably linked with interferences in endocrine pathways involving other gut peptides in this compromised condition.
[show abstract][hide abstract] ABSTRACT: Uricase catalyzes the oxidation of urate to form allantoin, carbon dioxide and hydrogen peroxide. In this article, we demonstrate for the first time the presence of a radical intermediate in-volved in the reaction mechanism. Such radical species was entrapped using 5-diethoxyphosphoryl-5-methyl-l-pyrroline N-oxide as spin trap and the relative adduct was detected by electron paramag-netic resonance (EPR) technique. A structure of such radical (5-hydroperoxy isourate) is proposed, through chemical results and density functional theory calculations of the EPR coupling constants.
Applied Magnetic Resonance 01/2007; 31:471-482. · 0.83 Impact Factor
[show abstract][hide abstract] ABSTRACT: Atherosclerosis is a complex disease that affects medium and large arteries, leading to the formation and progression of plaque. In this process the proteins play an essential role and as a consequence, proteomic-based strategies examining the protein content of cells or tissues could offer a useful approach for the study of plaque proteins. Due to the heterogeneous cell composition of plaque, proteome analysis of whole lesions is difficult, besides being also complicated by the presence of plasma proteins that cannot be completely eliminated. A good way to study variations in protein expression among series of gels is to construct a synthetic gel. This type of gel is obtained by averaging the positions, shapes and optical densities of spots in a given set of gels. To be included in the synthetic gel, spots must be found in at least three gels. To obtain a profile representative of the proteome of atherosclerotic plaque, cancelling its high variability, we constructed a synthetic gel using an average of ten carotid plaque samples. We then compared it with an equivalent synthetic gel constructed using ten plasma samples from the same carotid surgery patients. For the comparison of two synthetic gels (plasma/plaque) we could discriminate plasma proteins from plaque proteins. Besides analysis of spots common to plasma, the synthetic gel is useful to detect spots exclusive to plaque, thus simplifying a very complex mixture.
International journal of immunopathology and pharmacology 01/2007; 20(3):637-42. · 2.99 Impact Factor
[show abstract][hide abstract] ABSTRACT: B-cell chronic lymphocytic leukemia (B-CLL) is an adult-onset highly heterogeneous malignancy characterized by a cells resistance to apoptosis rather than to highly proliferative cells. In previous research, we evidenced an imbalance of purine metabolism in B-CLL cells. Since the extracellular adenosine has been proved to induce apoptosis via A2b receptor, enzymes involved in adenosine metabolism could play an important role in apoptosis resistance of B-CLL cells. We prepared a microarray chip for the analysis of 50 selected genes that could be of interest in B-CLL: enzymes of purine de-novo, salvage and catabolic pathway, oxidative stress enzymes, and apoptotis-related proteins. Preliminary results identify many genes of purine metabolism that exhibit low or high expression, while genes involved in signal transduction and apoptosis exhibit lower alterations even if of remarkable interest. This application of microarray technique seems promising and at least a subset of these genes will be valid candidates for further studies.
[show abstract][hide abstract] ABSTRACT: This study was carried out on carotid artery plaque and plasma of 50 patients. We analyzed uric acid, hypoxanthine, xanthine, and allantoin levels to verify if enzymatic purine degradation occurs in advanced carotid plaque; we also determined free radicals and sulphydryl groups to check if there is a correlation between oxidant status and purine catabolism. Comparing plaque and plasma we found higher levels of free radicals, hypoxanthine, xanthine, and a decrease of some oxidant protectors, such as sulphydryl groups and uric acid, in plaque. We also observed a very important phenomenon in plaque, the presence of allantoin due to chemical oxidation of uric acid, since humans do not have the enzyme uricase. The hypothetical elevated activity of xanthine oxidase in atherosclerosis could be reduced by specific therapies using its inhibitors, such as oxypurinol or allopurinol.
[show abstract][hide abstract] ABSTRACT: Using a combination of chromatographic and NMR techniques, the presence of D-chiro-inositol and its two galacto-derivatives is demonstrated in Mucuna pruriens seeds. The quantities detected explain the well-established antiglycaemic effect of Mucuna pruriens seeds.
Phytotherapy Research 01/2006; 19(12):1057-60. · 2.07 Impact Factor
[show abstract][hide abstract] ABSTRACT: Adenosine kinase is a well-known enzyme which catalyzes the phosphorylation of adenosine to AMP: Its metabolic and kinetic properties are well studied. Here, we report new properties of rat liver enzyme, demonstrating a new reaction: ADP can be a phosphate donor instead ATP, according to the reaction: adenosine + ADP --> 2AMP) demonstrating the efficiency of AdK to phosphorylate adenosine, also starting from ADP. Cells could exploited this property in situations in which ATP levels are strongly decreased and ADP decreases slowly.