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ABSTRACT: Recent reports suggest increased incidence and severity of Clostridium difficile-associated diseases. These facts have raised the need for additional clarification of pathogenesis and for a search for new therapeutic strategies. This study evaluated the effects of the polysaccharide fucoidin, an L-selectin blocker, on toxin-A-induced mouse enteritis. Fucoidin (25 mg/kg) or saline (0.1 ml) were injected systemically (ocular plexus) 5 min prior to local challenge with toxin A (5 microg/ileal loop) or phosphate-buffered saline (PBS). Intestinal fluid volume/length and ileal loop weight/length ratios were calculated 3 h later. Ileal tissues were collected for histopathology and measurement of myeloperoxidase and adenosine deaminase activity. Fucoidin significantly (P < 0.05) prevented the toxin-A-induced increase in weight/length and volume/length ratios and reduced mucosal disruption, as shown in histopathology. Fucoidin also significantly (P < 0.05) reduced toxin-A-induced myeloperoxidase and adenosine deaminase activities. In conclusion, fucoidin reduces tissue injury and inflammation in toxin-A-induced mouse enteritis.
Digestive Diseases and Sciences 04/2008; 53(4):990-6. · 2.12 Impact Factor
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ABSTRACT: Previous studies have described pro- and anti-inflammatory activities displayed by the latex from Calotropis procera. This report aims to clarify these observations and shows that such activities can be segregated from the whole latex.
The latex was divided into water-soluble fractions devoid of poly-isoprene by centrifugation and dialysis and both the activities were assayed by the peritonitis model in rats. The drugs dexamethasone, thalidomide, meclizine, indomethacin and celecoxib were used to modulate the inflammatory stimuli.
Inflammation in rats was observed 2 h after intraperitoneal administration of the stimulus (DL fraction) in a dose dependent manner. This activity was inhibited by previous intravenous injection of dexamethasone, thalidomide and meclizine. Indomethacin and celecoxib did not reverse inflammation. These results suggest the involvement of histamine release and TNF-alpha mediated inflammation while prostaglandins seem not to be required. The anti-inflammatory fraction (NDL) inhibited inflammation triggered by proinflammatory fraction (DL) suggesting that NDL ought to follow a similar pathway of action to that of the anti-inflammatory drugs that were able to inhibit inflammation triggered by DL.
Pro- and anti-inflammatory activities of the latex are displayed by compounds suitable to be fractionated on the basis of their molecular size.
Inflammation Research 01/2007; 55(12):559-64. · 2.11 Impact Factor
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ABSTRACT: We have investigated the anti-inflammatory and antimicrobial effect of the lectin from Lonchocarpus sericeus seeds (LSL) in a model of infectious peritonitis in adult Wistar rats. Animals were treated with saline or LSL (10 mg kg(-1), i.v) immediately and 6 h after the induction of peritonitis via cecal ligation and single puncture. Twelve hours after surgery, animals were killed and the infectious process was monitored by total and differential count of cells from blood and peritoneal washing liquid, adenosine deaminase activity, antibiogram and the number of viable bacteria of the peritoneal cavity. LSL treatment decreased the inflammatory response evoked by the induction of peritonitis, as seen by the inhibition of neutrophil migration into peritoneal cavities, leucocytosis and reduction of adenosine deaminase activity in the peritoneal fluid. All these effects were reversed by the lectin association to N-acetyl-glucosamine. LSL in-vitro did not show any antimicrobial action, but promoted a marked decrease of the viable bacterial population in peritoneal cavities. In conclusion, LSL inhibited the inflammatory response and the bacterial colonization of infectious peritonitis in rats.
Journal of Pharmacy and Pharmacology 08/2005; 57(7):919-22. · 2.17 Impact Factor
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ABSTRACT: Adenosine is an important signaling molecule for many cellular events. Adenosine deaminase (ADA) is a key enzyme for the control of extra- and intra-cellular levels of adenosine. Activity of ADA was detected in hemolymph of B. glabrata and its optimum assay conditions were determined experimentally. The pH variation from 6.2 to 7.8 caused no significant change in ADA activity. Using adenosine as a substrate, the apparent Km at pH 6.8 was 734 micromols.L(-1). Highest activity was found at 37 degrees C. Standard assay conditions were established as being 15 minutes of incubation time, 0.4 microL of pure hemolymph per assay, pH 6.8, and 37 degrees C. This enzyme showed activities of 834 +/- 67 micromol.min(-1).L(-1) (25 degrees C) and 2029 +/- 74 micromol.min(-1).L(-1) (37 degrees C), exceeding those in healthy human serum by 40 and 100 times, respectively. Higher incubation temperature caused a decrease in activity of 20% at 43 degres C or 70% at 50 degrees C for 15 minutes. The ADA lost from 26% to 78% of its activity when hemolymph was pre-incubated at 50 degrees C for 2 or 15 minutes, respectively. Since the ADA from hemolymph presented high levels, it can be concluded that in healthy and fed animals, adenosine is maintained at low concentrations. In addition, the small variation in activity over the 6.2 to 7.8 range of pH suggests that adenosine is maintained at low levels in hemolymph even under adverse conditions, in which the pH is altered.
Brazilian Journal of Biology 06/2005; 65(2):371-6. · 0.69 Impact Factor
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ABSTRACT: Latex from Calotropis procera is widely used in folk medicine as a rich source of biologically active compounds capable of promoting diverse benefits such as control of dermal fungal infections, antimicrobial activities and pain relief among other useful properties. The aim of this work was to characterize the anti-inflammatory effect of a non-dialysable protein fraction recovered from the rubber-free latex using three different experimental models when administrated intravenously. In vivo neutrophil migration induced by carrageenin (500 microg) was severely inhibited by doses of latex proteins reaching maximum inhibition (80%) at 100 mg/kg. Paw edema exacerbated by the effect of carrageenin was almost completely suppressed after 4 hours and was controlled within the first hour following latex protein administration. However, the same latex fraction was completely unable to control the paw edema invoked with dextran stimulation (400 microg), suggesting that the inhibitory effect of the latex is likely to be cell-mediated. Iphosphamide-induced vesical edema in mice was also largely prevented by the latex protein fraction. These results indicate that an effect similar to that of mesna, the classical drug used for this purpose, is operative. Our findings suggest that the sample tested seems to act over a wide spectrum as a novel anti-inflammatory agent. The results also suggest that the active molecules are of a proteinaceous nature despite the presence of numerous secondary metabolites naturally occurring in the C. procera latex.
Planta Medica 01/2005; 70(12):1144-9. · 2.15 Impact Factor
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ABSTRACT: The water soluble fraction of Ageratum conyzoides L. (WSF) was studied in isolated rat uterus and intestinal smooth muscles in order to evaluate its popular use as a spasmolytic. WSF (0.2 and 0.4 mg/mL) increased EC(50) values and decreased maximum responses to acetylcholine and calcium chloride. WSF (0.5-3.3 mg/mL) also produced direct myorelaxant effect on smooth muscle preparations. Theophylline (10(-3) M) potentiated the relaxant action of WSF. Theophylline also prevented the decrease in maximum response promoted by WSF in acetylcholine concentration-effect curves. These results seem to be partially linked to calcium mobilization. The data also suggest that WSF could act synergistically with theophylline in the inhibition of cyclic AMP phosphodiesterase. The results give support to the popular medicinal indications of the plant.
Phytotherapy Research 04/2000; 14(2):130-2. · 2.09 Impact Factor
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ABSTRACT: Intraperitoneal injection of pilocarpine (0.75-3.0 mg/kg) caused a dose-related seminal emission in adult male rats. The seminal emission response to 3 mg/kg of pilocarpine was greatly reduced in atropinized (5 and 10 mg/kg, SC) animals, suggesting a cholinomimetic effect. Nw-nitro-L-arginine methyl ester (5, 10, and 20 mg/kg, SC), a nitric oxide synthesis inhibitor, also inhibited the pilocarpine-induced seminal emission, which was reversed by L-arginine (600 mg/kg, SC) or by coinjection of sodium nitroprusside (0.5 mg/kg, SC). Urine analysis for levels of nitric oxide metabolites, nitrate/nitrite (NO3-/NO2-), showed marked alterations in accordance with the drug treatments. The results suggest that nitric oxide mediates the inhibitory neurotransmission responsible for seminal emission in pilocarpine stimulated rats.
General Pharmacology 01/2000; 33(6):479-85.
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ABSTRACT: We studied the contribution of periarthritis and synovitis to gait disturbance in zymosan (Zy)-induced arthritis.
Sixty Wistar rats were subjected to injection of Zy (1 mg) into their right knee joints. A first group of animals (GI) had Zy injected through the intact skin. A second group (GII) had Zy injected directly into the articular cavity after excision of the skin and subcutaneous tissue surrounding the joint. Gait disturbance was evaluated using the rat-knee joint incapacitation test. Increase in vascular permeability and cell influx were assessed in joint fluids and joint histology was performed.
Zy injection induced a dose-dependent gait disturbance which was maximal at the third/fourth hour of arthritis, being significantly greater in GI rats, whereas cell influx (neutrophils > or = 80%) was maximal at the sixth hour. Cell influx and increase in vasopermeability did not differ between both groups. Histology revealed no significant difference between GI and GII. A third group (GIII), subjected to immune-complex arthritis, that received anti-bovine serum albumin (BSA) antibodies intra-articularly and BSA i.v., did not present gait disturbance, despite the increase in cell counts.
Vascular permeability increase and cell influx are phenomena independent of gait disturbance. Neutrophils do not seem to contribute to development of gait disturbance in Zy arthritis. Sensitization of specific pain receptors in periarticular rather than in synovial tissue is responsible for gait disturbance in Zy-induced arthritis.
Inflammation Research 10/1999; 48(9):485-90. · 2.11 Impact Factor
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ABSTRACT: The mechanism of action of lithium (Li) alone or with pilocarpine (Pilo), focusing on muscarinic and dopaminergic systems and also on phosphoinositide metabolism was studied. Li (3 mEq/kg) administered to rats once (1 d) or daily for 7 days (7 d), 24 h before Pilo (15 mg/kg), exacerbated cholinergic signs, leading to tremors. convulsions and brain lesions. Increases in muscarinic receptors (MR) of 29 and 49% were observed in the hippocampus after atropine (Atro) and Li-Atro-Pilo treatments, respectively, as compared to controls (Atro) and the Li-Pilo group (Li-Atro-Pilo). In the striatum, except for the 37% increase in the Li-Atro (50 mg/kg)-Pilo group as compared to the Li-Pilo one, no other changes were observed in MR. A decrease of 32% on average in D2-like receptors (D2R) was detected in the hippocampus in the group Li-7d. On the contrary, in the striatum an increase (25%) in the Li-7d group was observed and this effect was blocked by Li-Pilo. As far as inositol phosphates (IP) and phosphatidylinositol-4,5-biphosphate (PIP2) metabolism is concerned, Li caused a decrease (28%) and an increase (60%) in IP and PIP2 accumulations, respectively, in hippocampus slices while Pilo only altered IP accumulation (32% decrease). In this area the association of Li-Atro (10 mg/kg)-Pilo also caused a decrease (36%) in PIP2 as compared to the Li-Pilo group. In striatal slices, except for the Li, Atro (10 mg/kg) and Li-Atro (10 mg/kg)-Pilo groups which showed a decrease (33 40%) in IP accumulation, no other alteration was detected. The potentiation of the effect of Pilo by Li does not seem to depend on the PI metabolism, but instead on its involvement with muscarinic and dopaminergic systems.
Neurochemistry International 11/1998; 33(4):299-306. · 2.86 Impact Factor
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ABSTRACT: Although oxidative stress has been implicated in the pathogenesis of neurodegenerative diseases, data found in the literature are still a matter of controversy.
To study lipid peroxidation and nitrite plus nitrate levels in brain specimens (frontal, parietal, temporal, and occipital cortices) from 8 patients with Alzheimer's disease (AD) in comparison to 6 young and 7 age-matched controls.
Lipid peroxidation was estimated by the thiobarbiturate test for malonaldehyde and nitrate/nitrite using the Griess method.
Our results show a clear malonaldehyde increase tendency in all brain areas from AD cases in relation to older individuals and younger controls. In temporal cortex there was no difference between AD cases and age-matched controls. We suggest that this may be due to incipient temporal cortex damage in control individuals and that this area could be more susceptible to age-related changes. We showed that nitrite plus nitrate levels significantly decrease in brain areas of AD cases in relation to young controls. Except for the frontal cortex, there was a trend for a decreased concentration of nitrite/nitrate in the aged group in all brain areas studied as compared with young controls.
Our results support a major role for lipid peroxidation alterations in cerebral cortex of AD patients and showed not only a decrease in nitrite/nitrate levels in frontal cortex of AD cases in relation to young and old individuals, but also a reduction in these nitric oxide metabolites in the other cortical areas as related to young controls.
Gerontology 46(4):179-84. · 2.78 Impact Factor
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ABSTRACT: The mechanism of action of lithium (Li) alone or with pilocarpine (Pilo), focusing on muscarinic and dopaminergic systems and also on phosphoinositide metabolism was studied. Li (3 mEq\kg) administered to rats once (1 d) or daily for 7 days (7 d), 24 h before Pilo (15 mg\kg), exacerbated cholinergic signs, leading to tremors, convulsions and brain lesions. Increases in muscarinic receptors (MR) of 29 and 49% were observed in the hippocampus after atropine (Atro) and Li-Atro-Pilo treatments, respectively, as compared to controls (Atro) and the Li-Pilo group (Li-Atro-Pilo). In the striatum, except for the 37% increase in the Li-Atro (50 mg\kg)-Pilo group as compared to the Li-Pilo one, no other changes were observed in MR. A decrease of 32% on average in D2-like receptors (D2R) was detected in the hippocampus in the group Li-7d. On the contrary, in the striatum an increase (25%) in the Li-7d group was observed and this effect was blocked by Li-Pilo. As far as inositol phosphates (IP) and phosphatidylinositol-4,5-biphosphate (PIP2) metabolism is concerned, Li caused a decrease (28%) and an increase (60%) in IP and PIP2 accumulations, respectively, in hippocampus slices while Pilo only altered IP accumulation (32% decrease). In this area the association of Li-Atro (10 mg\kg)-Pilo also caused a decrease (36%) in PIP2 as compared to the Li-Pilo group. In striatal slices, except for the Li, Atro (10 mg\kg) and Li-Atro (10 mg\kg)-Pilo groups which showed a decrease (33–40%) in IP accumulation, no other alteration was detected. The potentiation of the effect of Pilo by Li does not seem to depend on the PI metabolism, but instead on its involvement with muscarinic and dopaminergic systems.
Neurochemistry International.
