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In-vitro Experiments (in-vitro + experiment)
Selected AbstractsMedicinal plants in Suriname: hypotensive effect of Gossypium barbadenseJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2004J. A. Hasrat ABSTRACT In traditional medicine Gossypium barbadense L. is used against hypertension. Looking for a scientific basis for this use, the blood-pressure-lowering effect of the decoction of the leaves was confirmed. Fraction II (frII) of the crude extract of G. barbadense showed a dose-dependent hypotensive effect in anaesthetized rats. In hexamethonium-treated rats, the blood-pressure-lowering effect of frII was almost abolished. A small decrease of the blood-pressure-lowering effect was followed by an increase in the blood pressure. Phentolamine antagonized the increase in blood pressure in hexamethoniumtreated rats. High doses of atropine (4 mg/rat) suppressed both depressor and heart effects. In-vitro experiments revealed that atropine did not antagonize the contraction of the ileum of the rat. Tripelennamine in a concentration of 100 ,g could not influence the contraction either, whereas 300 ,g did. In the guinea-pig ileum 10 ,g tripelennamine did not reduce the contraction significantly. In the mechanism of action of frII, acetylcholine receptors could be involved, but not histaminergic or adrenergic receptors. Although it is still not known which compound(s) in G. barbadense is (are) the active substance(s), the results obtained may explain the use of this plant in traditional medicine in Suriname. [source] Calpain cleavage of collapsin response mediator proteins in ischemic mouse brainEUROPEAN JOURNAL OF NEUROSCIENCE, Issue 4 2007Susan X. Jiang Abstract Collapsin response mediator proteins (CRMPs) are important brain-specific proteins with distinct functions in modulating growth cone collapse and axonal guidance during brain development. Our previous studies have shown that calpain cleaves CRMP3 in the adult mouse brain during cerebral ischemia [S.T. Hou et al. (2006) J. Neurosci., 26, 2241,2249]. Here, the expression of all CRMP family members (1,5) was examined in mouse brains that were subjected to middle cerebral artery occlusion. Among the five CRMPs, the expressions of CRMP1, CRMP3 and CRMP5 were the most abundant in the cerebral cortex and all CRMPs were targeted for cleavage by ischemia-activated calpain. Sub-cellular fractionation analysis showed that cleavage of CRMPs by calpain occurred not only in the cytoplasm but also in the synaptosomes isolated from ischemic brains. Moreover, synaptosomal CRMPs appeared to be at least one-fold more sensitive to cleavage compared with those isolated from the cytosolic fraction in an in-vitro experiment, suggesting that synaptosomal CRMPs are critical targets during cerebral ischemia-induced neuronal injury. Finally, the expression of all CRMPs was colocalized with TUNEL-positive neurons in the ischemic mouse brain, which further supports the notion that CRMPs may play an important role in neuronal death following cerebral ischemia. Collectively, these studies demonstrated that CRMPs are targets of calpains during cerebral ischemia and they also highlighted an important potential role that CRMPs may play in modulating ischemic neuronal death. [source] Phosphate-solubilizing potential of the nematophagous fungus Arthrobotrys oligosporaJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 2 2006Robin Duponnois Abstract The nematophagous fungus Arthrobotrys oligospora was tested in vitro and in vivo for its ability to solubilize rock phosphate. Three types of rock phosphate (RP) from Burkina Faso (KRP), Senegal (TRP), and Mali (TIRP) were used at four concentrations for the in-vitro experiment. All three types of RP were solubilized by the fungus. The maximum quantity of P recovered in solution was obtained with TRP, 12.5% for an application of 1 g L,1. The effect of TRP and A. oligospora applied separately or in combination was tested in vivo on the growth of A. holosericea. In a P-deficient soil without addition of RP, P solubilization was increased by addition of A. oligospora. The P uptake by plants growing in soil amended with TRP and inoculated with A. oligospora was significantly higher compared to noninoculated controls, thus demonstrating the ability of the fungus to solubilize additional phosphate from RP in vivo. [source] Defense mechanism to oxidative DNA damage in glial cellsNEUROPATHOLOGY, Issue 2 2004Takashi Iida Astrocytosis is a sequential morphological change of astrocytic reaction to tissue damage, and is associated with regulation of antioxidant defense mechanisms to reduce oxidative damage. The repair enzymes to oxidative DNA damage, oxidized purine-nucleoside triphosphatase (hMTH1) and a mitochondrial type of 8-oxoguanine DNA glycosylase (hOGG1,2a) in brain tumors and neurons of Alzheimer's disease, were previously reported. In the present study, glial expression of these repair enzymes under such pathological conditions as cerebrovascular diseases and metastatic brain tumors, were investigated. Furthermore, an in-vitro experiment using a glioma cell-line under oxidative stress was performed to verify the immunohistochemical results of post-mortem materials. As a result, hOGG1,2a immunoreactivities in reactive astrocytes were more intense than those to hMTH1. Oligodendrocytes of acute or subacute stage of brain infarction were strongly immunoreactive to both repair enzymes. In-vitro study revealed that, hOGG1,2a is constitutively expressed in both untreated glioma cells and the glioma cells under oxidative stress. However, although no immunoreactivity to hMTH1 was found in the control cells, accumulation of hMTH1 was rapidly induced by oxidative stress. These results indicate that the two repair enzymes to oxidative DNA damage are differentially regulated in glial cells, and that there is a difference in the expression of the repair enzymes between reactive astrocytes and oligodendrocytes. [source] Physicochemical interactions between drugs and superdisintegrantsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2008Nelly Fransén We have evaluated the interactions between superdisintegrants and drugs with different physicochemical characteristics, which may affect the in-vivo absorption e.g. after mucosal administration. The binding of sodium salicylate, naproxen, methyl hydroxybenzoate (methylparaben), ethyl hydroxybenzoate (ethylparaben), propyl hydroxybenzoate (propylparaben), atenolol, alprenolol, diphenhydramine, verapamil, amitriptyline and cetylpyridinium chloride monohydrate (CPC) to different superdisintegrants (sodium starch glycolate (SSG), croscarmellose sodium (CCS) and crospovidone) and one unsubstituted comparator (starch) was studied spectrophotometrically. An indication of the in-vivo effect was obtained by measuring the interactions at physiological salt concentrations. SSG was investigated more thoroughly to obtain release profiles and correlation between binding and ionic strength. The results showed that the main interactions with the anionic hydrogels formed by SSG and CCS were caused by ion exchange, whereas the neutral crospovidone exhibited lipophilic interactions with the non-ionic substances. The effect of increased ionic strength was most pronounced at low salt concentrations and the ion exchange interactions were almost completely eradicated at physiological conditions. The release profile of diphenhydramine was significantly affected by the addition of salt. It was thus concluded that the choice of buffer was of great importance for in-vitro experiments with ionic drugs. At physiological salt concentrations the interactions did not appear to be strong enough to influence the in-vivo bioavailability of any of the drug molecules. [source] Effects of oral administration of extracts of Hypericum perforatum (St John's wort) on brain serotonin transporter, serotonin uptake and behaviour in miceJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 12 2004Kazufumi Hirano The pharmacological effects of extracts of Hypericum perforatum (St John's wort) were characterized in-vitro and ex-vivo, in relation to its behavioural effects. In in-vitro experiments, St John's wort inhibited brain synaptosomal [3H]serotonin uptake in mice with little effect on specific [3H]paroxetine binding. For selective serotonin-reuptake inhibitors (SSRIs), the IC50 value for [3H]serotonin uptake (molar concentration of unlabelled drug necessary to displace 50% of specific uptake) correlated well with the inhibition constant Ki value for [3H]paroxetine binding in mouse brain. Oral administration of St John's wort (900 mg kg,1), paroxetine (1 mg kg,1) and sertraline (10 mg kg,1) brought about significant increases in the Km value for [3H]serotonin uptake into brain synaptosomes 4 h later, and only SSRIs suppressed specific [3H]paroxetine binding in mouse brain. St John's wort and SSRIs significantly inhibited marble-burying behaviour in mice and the time-course of attenuation of this behaviour by St John's wort was similar to that of [3H]serotonin uptake inhibition. In the forced swimming test, St John's wort, but not SSRIs, suppressed the immobility time of mice after oral administration. These results provide the first in-vivo evidence to suggest that the mode of antidepressant action of St John's wort differs from that of SSRIs. Thus, this study may have a significant impact on phytotherapy with St John's wort. [source] In-vitro and in-vivo evaluation of pH-responsive polymeric micelles in a photodynamic cancer therapy modelJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2001J. Taillefer pH-sensitive polymeric micelles of randomly and terminally alkylated N-isopropylacrylamide copolymers were prepared and characterized. Aluminium chloride phthalocyanine (AlClPc), a second generation sensitizer for the photodynamic therapy of cancer, was incorporated in the micelles by dialysis. Their photodynamic activities were evaluated in-vitro against EMT-6 mouse mammary tumour cells and in-vivo against EMT-6 tumours implanted intradermally on each hind thigh of Balb/c mice. pH-sensitive polymeric micelles were found to exhibit greater cytotoxicity in-vitro than control Cremophor EL formulations. In the presence of chloroquine, a weak base that raises the internal pH of acidic organelles, in-vitro experiments demonstrated the importance of endosomal/lysosomal acidity for the pH-sensitive polymeric micelles to be fully effective. Biodistribution was assessed by fluorescence of tissue extracts after intravenous injection of 2 ,mol kg,1 AlClPc. The results revealed accumulation of AlClPc polymeric micelles in the liver, spleen and lungs, with a lower tumour uptake than AlClPc Cremophor EL formulations. However, polymeric micelles exhibited similar activity in-vivo to the control Cremophor EL formulations, demonstrating the higher potency of AlClPc polymeric micelles when localized in tumour tissue. It was concluded that polymeric micelles represent a good alternative to Cremophor EL preparations for the vectorization of hydrophobic drugs. [source] In-vitro Antioxidant and In-vivo Photoprotective Effect of Three Lyophilized Extracts of Sedum telephium L. LeavesJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2000FRANCESCO BONINA Sedum telephium L. is a medicinal plant used in antiquity to cure many types of inflammatory skin diseases. The leaves (without the external cuticle), are used to promote healing and reduce skin inflammation and pain, and contain various components. We found two major components: flavonol glycosides and polysaccharides, with molecular weight between 13 000 and 13 500 Da. We evaluated the in-vitro antioxidant and in-vivo skin photoprotective effects of three lyophilized extracts obtained from the juice of S. telephium L. leaves: a total lyophilized juice, a lyophilized flavonolic fraction, and a lyophilized polysaccharidic fraction. Two in-vitro models were used: the bleaching of the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH*) radical, and the protective effect against UV-induced peroxidation on phosphatidylcholine multilamellar vesicles, as model membranes. The antioxidant/radical scavenging activity of each lyophilized extract was also assessed in-vivo by determining their ability to reduce UVB-induced skin erythema (monitored by reflectance spectrophotometry) in healthy human volunteers. The findings of the in-vitro experiments clearly demonstrated that, unlike the lyophilized polysaccharidic fraction, the lyophilized flavonolic fraction and total lyophilized juice possess strong antioxidant/free radical scavenging properties, which are likely due to phenolic compounds. Consistent with these findings, gel formulations of both the total lyophilized juice and, to a greater degree, the lyophilized flavonolic fraction appeared to possess a strong protective effect against UV-induced skin erythema in-vivo, whereas the lyophilized polysaccharidic fraction was completely ineffective. The in-vitro and in-vivo results suggest that, both the total lyophilized juice and, in particular, the lyophilized flavonolic fraction, but not the lyophilized polysaccharidic fraction of S. telephium L. leaves, have photoprotective effects against UVB-induced skin damage. [source] Reduction of the Potential Anticancer Drug Oracin in the Rat Liver In-vitroJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 5 2000BARBORA SZOTÁKOVÁ Studies on the metabolism of the potential cytostatic drug oracin have shown that a principal metabolite of oracin is 11-dihydrooracin (DHO). We conducted in-vitro experiments to investigate the extent of oracin carbonyl reduction in microsomal or cytosolic fractions and to find out the enzymes involved under these conditions. Among several inducers of rat cytochrome P450 only 3-methylcholanthrene caused a significant (P < 0.01) stimulation (1.9 times) of DHO production in microsomal fraction and the specific P4501A inhibitor ,-naphthoflavone significantly (P < 0.01) decreased (twice) the induced reduction activity. Cytochrome P4501A participates in oracin reduction in microsomes. 18,-Glycyrrhetinic acid, a specific inhibitor of hydroxysteroid dehydrogenase, significantly (P < 0.01) inhibited the production of DHO in the microsomal fraction (>95% inhibition) in comparison with the non-inhibited reaction. Statistically significant (P < 0.01) inhibition (95%) of DHO formation was caused by metyrapone, which is also the substrate of 11,-hydroxysteroid dehydrogenase. The main microsomal enzyme which catalyses the carbonyl reduction of oracin is probably 11,-hydroxysteroid dehydrogenase. Important oracin reduction to DHO in the cytosolic fraction was found. According to its specific sensitivity towards quercitrin (inhibition by 99%, P < 0.01), the enzyme responsible for DHO formation in the rat liver cytosol is postulated to be carbonyl reductase. [source] Pharmacodynamics of S-2150, a Simultaneous Calcium-blocking and ,1 -Inhibiting Antihypertensive Drug, in RatsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2000TORU ISHIBASHI The in-vivo pharmacodynamics of S-2150, a newly developed dual-blocking type antihypertensive drug, was evaluated following intravenous infusion to rats. Previous in-vitro studies showed that the drug has two distinct mechanisms of antihypertensive effect,calcium-channel blocking activity and ,1 -adrenoceptor antagonism,which could be explained by a combination of two different pharmacodynamic models. The present in-vivo study showed that S-2150 also displays a complex pharmacodynamic profile (as measured by the decrease in mean blood pressure), which could be described by a combination of two sigmoid Emax models independently connected with the central compartment and the effect compartment. These results suggested that the dual-blocking mechanism of S-2150, which has been observed in in-vitro experiments, was also evaluated by the pharmacodynamic analysis of in-vivo experimental data. [source] | ||||||||||