PubMed Health⌕ Search

Biomedical subjects

R Elias

Publications and source records attributed to R Elias.

At least 19 recordsLinked to original sources
PubMed2006

Extent of atherosclerosis and prognosis of patients with aneurysmal subarachnoid haemorrhage.

BACKGROUND AND PURPOSE: Atherosclerosis impairs the endothelial dependent vasodilatation and may change the diameter and plasticity of cerebral vessels. The aim of this study was to investigate if an index of the occurrence of atherosclerosis is associated with the risk of delayed cerebral ischemia or poor outcome after subarachnoid haemorrhage. METHODS: To assess the likelihood of atherosclerosis we used a modified version of the Framingham Heart Study Coronary Heart Disease Prediction Chart. The relation of this index to the occurrence of delayed cerebral ischemia was studied by means of survival analysis and to poor outcome by regression analysis. A multivariate analysis was used to investigate the independent contribution of the atherosclerosis index. RESULTS: Three hundred and twenty three patients were retrieved from our database from the period 1997 to 2004. The index of atherosclerosis related to a good clinical condition on admission (p = 0.01). A high risk of atherosclerosis independently predicted poor outcome (OR 4.3; 95%CI 1.6-12). This was not caused by an increase in the occurrence of delayed cerebral ischemia (HR 1.1; 95%CI 0.6-2.1), but, in part, by a marked decrease in recurrent bleeding in patients with no or minor atherosclerosis. CONCLUSIONS: An index of the occurrence of atherosclerosis is related to prognosis after subarachnoid haemorrhage. The use of the score may focus attention on patients at risk for poor outcome after subarachnoid haemorrhage.

Adult↗
PubMed2005

Effects of Leontice smirnowii tuber monodesmosides and crude extract in carrageenan- and histamine-induced acute inflammation model of rats.

Leontice smirnowii is a member of the Berberidaceae family. We have recently reported the 1,1-diphenyl-2-picryl-hydrazyl radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, reducing power and metal chelating activities of L. smirnowii products. In the current study we investigated the possible effects of the crude extracts of L. smirnowii (CELS) and the monodesmoside's purified extract (MPE) of L. smirnowii in the carrageenan- and histamine-induced acute inflammation models in rats. The experiment revealed that CELS and MPE have anti-inflammatory effects, dose dependently in carrageenan-induced acute inflammation. On the other hand, their proinflammatory effects were surprisingly observed, especially in low doses, in the histamine-induced acute inflammation model. Summarizing these data, we may state that CELS and MPE exert their anti-inflammatory effects via non-histaminergic pathways.

Animals↗
PubMed2005

Screening of antiradical and antioxidant activity of monodesmosides and crude extract from Leontice smirnowii tuber.

Leontice smirnowii is a member of the Berberidaceae family. In the current study we investigated the possible antiradical and antioxidant activity of the monodesmosides (MLS) and crude extract (CELS) of Leontice smirnowii using different antioxidant tests: 1,1-diphenyl-2-picryl-hydrazyl (DPPH) free radical scavenging, scavenging of superoxide anion radical-generated non-enzymatic system, ferric thiocyanate (FTC) method, reducing power, hydrogen peroxide scavenging and metal chelating activities. Experiment revealed that MLS and CELS have an antioxidant effect concentration-dependently. Total antioxidant activity was performed according to FTC method. At the 30mug/ml concentration, the inhibition effects of MLS and CELS on peroxidation of linoleic acid emulsion were found to be 95.3% and 95.6%, respectively. On the other hand, percentage inhibition of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), alpha-tocopherol and trolox were found to be 98.2%, 98.5%, 84.0% and 87.9% inhibition of peroxidation of linoleic acid emulsion, respectively, at the same concentration. In addition, MLS and CELS had effective DPPH radical scavenging, superoxide anion radical scavenging, hydrogen peroxide scavenging, reducing power and metal chelating activities. Also, these various antioxidant activities were compared with BHA, BHT, alpha-tocopherol and trolox which were accepted as references antioxidants.

Antioxidants↗
PubMed2005

Acute anti-inflammatory activity of four saponins isolated from ivy: alpha-hederin, hederasaponin-C, hederacolchiside-E and hederacolchiside-F in carrageenan-induced rat paw edema.

The anti-inflammatory potential of alpha-hederin (monodesmoside) and hederasaponin-C from Hedera helix, and hederacolchisides-E and -F (bidesmosides) from H. colchica was investigated in carrageenan-induced acute paw edema in rats. Saponins and indomethacin were given orally in concentrations of 0.02 and 20mg/kg body wt. For the first phase of acute inflammation, indomethacin was found as the most potent drug. Alpha-hederin and hederasaponin-C were found ineffective, while hederacolchisides-E and -F showed slight anti-inflammatory effects on the first phase. For the second phase of acute inflammation, indomethacin and hederacolchiside-F were determined as very potent compounds. alpha-hederin was found ineffective for the second phase, either. Despite hederasaponin-C and -E were found effective in the second phase of inflammation, they were not found as effective as indomethacin and hederacolchiside-F. As a conclusion, hederasaponin-C, -E and -F, may exert their anti-inflammatory effects by blocking bradykinin or other inflammation mediators. The latter affect may occur via affecting prostaglandin pathways. Regarding the structure activity relationship, it is likely that sugars at C3 position and Rha7-Glcl-6Glc moiety at C28 position are essential for the acute anti-inflammatory effect.

Animals↗
PubMed2003

Acute and chronic antiinflammatory profile of the ivy plant, Hedera helix, in rats.

Hedera helix is a plant well-known as ivy or English ivy, and a member of the Araliaceae family. In the present study, we tested the possible antiinflammatory effects of a crude saponin extract (CSE) and a saponin's purified extracts (SPE) of Hedera helix in carrageenan- and cotton-pellet-induced acute and chronic inflammation models in rats. Both the CSE and SPE of Hedera helix were found to have antiinflammatory effects. The most potent drug screened was indomethacin (89.2% acute antiinflammatory effect), while the most potent extract screened was the CSE of Hedera helix at 100 and 200 mg/kg body wt. doses with 77% acute antiinflammatory effects. For testing chronic antiinflammatory (antiproliferative) effects, the cotton-pellet-granuloma test was conducted. Indomethacin was found to be the most potent drug in the chronic phase of inflammation, with 66% effect. The SPE of Hedera helix was more potent than the CSE in its chronic antiinflammatory effect (60% and 49%, respectively).

Animals↗
PubMed2001

Comparison of two floor mat lead dust collection methods and their application in pre-1950 and new urban houses.

This study investigated commercial floor mats as an alternative method to assess lead in residential dust in inner-city houses. Mats were placed for 3 weeks in interior entry-ways of 34 row houses built before 1950 and 17 new row houses in Baltimore City. A high volume sampler (an HVS3 floor model cyclone-based vacuum) and a hand-held portable cyclone sampler were used in the laboratory to collect side-by-side samples of mat dust. Both devices yielded comparable estimates of lead dust deposition, dust lead concentration, and dust deposition on field mat samples and had similar sampling efficiencies on mats spiked with various types of standard reference materials. The older houses had significantly higher daily lead dust deposition (mean = 130 micrograms/ft2/day by HVS3) than the newer houses (mean = 9 micrograms/ft2/day by HVS3), due to higher dust lead concentrations (mean = 1149 ppm vs mean = 107 ppm by HVS3) and not to differences in daily dust deposition (mean = 118 mg/ft2/day vs mean = 87 mg/ft2/day by HVS3) [corrected]. Mats were found to be a feasible method for the collection of dust that has accumulated for a known amount of time. Current wipe and vacuum methods do not allow for the estimation of dust deposition rates. Further research is needed to understand the role of floor mats as a risk assessment tool.

Air Pollution, Indoor↗
PubMed2001

In vitro antileishmanial activity of three saponins isolated from ivy, alpha-hederin, beta-hederin and hederacolchiside A(1), in association with pentamidine and amphotericin B.

The in vitro antileishmanial activity of three saponins isolated from ivy, alpha-hederin, beta-hederin and hederacolchiside A(1), was investigated on parasites of the species Leishmania mexicana, in their promastigote and amastigote forms compared with their toxicity versus human monocytes. The results showed that saponins exhibited a strong antiproliferative activity on all stages of development of the parasite but demonstrated a strong toxicity versus human cells. Association of subtoxic concentrations of saponins with antileishmanial drugs such as pentamidine and amphotericin B demonstrated that saponins could enhance the efficiency of conventional drugs on both the promastigote and the amastigote stages of development of the parasite. The results demonstrated moreover that the action of saponins on promastigote membrane was cumulative with those of amphotericin B.

Animals↗
PubMed2001

Rapid high-performance liquid chromatography analysis for the quantitative determination of oleuropein in Olea europaea leaves.

Olea europaea (Oleaceae) leaves of 14 different cultivars have been studied by a new isocratic HPLC method. Qualitative and quantitative determinations of principal compounds were established for each cultivar. Oleuropein concentration was determined for each sampled tree, using coumarin as internal standard. Bid el Haman, Chemlali, Meski, Cailletier, Tanche, a Verdale-Picholine hybrid, and Lucques, in particular, had high oleuropein concentrations and could be useful sources for industrial extractions.

Antihypertensive Agents↗
PubMed2001

Triterpenoid saponins from berries of Hedera colchica.

Fifteen triterpenoid saponins were isolated from the berries of Hedera colchica and their structures established on the basis of chemical and spectroscopic evidence. Among them, two are new compounds: coichiside A (3) and colchiside B (15) and four are described for the first time in the berries of Hedera colchica (compounds 1, 8, 9 and 11).

Magnetic Resonance Spectroscopy↗
PubMed2001

[Principal constituents from flowering aerial parts of wild pansy].

Dried flowering aerial parts of 12 harvested batches and 9 batches of commercial origin from Viola arvensis Murray were examined. The levels of principal compounds averaged respectively: total flavonoids 2.86 and 1.63%, rutin 1.15 and 0.57%, violanthin 0.80 and 0.82%, violarvensin 0.75 and 0.20%, mucilage 21.5 and 16.5%, total ashes 10.6 and 14.8%, potassium 2.75 and 2.85% and also salicy lic acid 0.11 and 0.09%. Saponins were not detected. Specifications were discussed for an European Pharmacopoeial monography.

Europe↗
PubMed2001

In vivo protection of photoreceptors from light damage by pigment epithelium-derived factor.

PURPOSE: To determine whether pigment epithelium-derived factor (PEDF) exhibits neurotrophic and neuroprotective activities in vivo for photoreceptor cells. METHODS: Sprague-Dawley albino rats were injected intravitreally with 2 microg PEDF or a mixture of 1 microg basic fibroblast growth factor (bFGF)/1 microg PEDF in a volume of 1 microl phosphate-buffered saline (PBS). Animals were exposed to constant light for different periods at an illuminance level of 1200 to 1500 lux. The electroretinogram (ERG) waveforms of both eyes in the same animal were simultaneously recorded to evaluate functional protection. The morphologic protection was evaluated by quantitative histology. RESULTS: Intravitreal injection of PEDF before exposure to constant light resulted in significant morphologic and functional protection of photoreceptor cells in the retina of light-damaged rats. This protection depended on the duration and severity of light damage. The protection was eliminated by extending the light exposure to 10 days. Injection of PEDF at 0, 1, and 2 days after constant light exposure did not provide significant protection above that seen in PBS-injected eyes. Combination of PEDF with bFGF improved functional protection of photoreceptor cells. CONCLUSIONS: The data demonstrate that PEDF protected photoreceptor cells against light damage. This is significant, because it may open new avenues for the study of molecular mechanisms underlying degenerative processes. This, in turn, may lead to the development of therapeutic strategies for the prevention and treatment of degenerative diseases of the retina.

Animals↗
PubMed2000

Artificial ecosystem selection.

Artificial selection has been practiced for centuries to shape the properties of individual organisms, providing Darwin with a powerful argument for his theory of natural selection. We show that the properties of whole ecosystems can also be shaped by artificial selection procedures. Ecosystems initiated in the laboratory vary phenotypically and a proportion of the variation is heritable, despite the fact that the ecosystems initially are composed of thousands of species and millions of individuals. Artificial ecosystem selection can be used for practical purposes, illustrates an important role for complex interactions in evolution, and challenges a widespread belief that selection is most effective at lower levels of the biological hierarchy.

Biological Evolution↗
PubMed2000

Recoverin negative photoreceptor cells.

Recoverin, a calcium-binding protein, is unique with respect to its cellular regulation. It is present in retinal rods, cones, cone bipolar cells, and in a rare population of cells in the ganglion cell layer. Inappropriate turn-on or turn-off of recoverin expression has been reported both in small cell lung carcinoma cells from patients with cancer-associated retinopathy (Matsusara et al. [1996] Br. J. Cancer 74:1419-1422; Adamus et al. [1998] J. Autoimmun. 11: 523-533; Ohguro et al. [1999] Invest. Ophthalmol. Vis. Sci. 40:82-89) and in cultured retinal neurons (McGinnis et al. [1999] J. Neursci. Res. 55:252-260). In a recent report using double labeling immunofluorescence microscopy methods with antibodies against either rhodopsin and recoverin or arrestin and recoverin, two unique cell phenotypes, rhodopsin-positive and recoverin-negative, and arrestin-positive, and recoverin-negative were observed in vitro. These two unique cell types could be nonphotoreceptor cells in which rhodopsin and arrestin are inappropriately turned on or they are photoreceptor cells in which the recoverin gene is inappropriately turned off. In this study, multiple antibodies were used to study, on a single-cell basis, whether the photoreceptor cell-specific marker, rhodopsin, is inappropriately expressed in nonphotoreceptor cells in our retinal neuronal culture system. We also examined the hypothesis that the two unique cell phenotypes represent the same population of cells. A triple labeling method has been established to visualize recoverin, rhodopsin, and arrestin protein expression simultaneously in cultured retinal neurons. Our data clearly and directly demonstrate that the previously described unique cell phenotypes are the same population of cells, rod photoreceptors. The existence of recoverin-negative photoreceptors demonstrates that the recoverin gene can be regulated independently of other photoreceptor cell-specific proteins and suggests that this primary cell culture may be useful as a model system for investigating the illicit expression of the recoverin gene in cancer associated retinopathy.

Animals↗
PubMed2000

Antileishmanial activity of three saponins isolated from ivy, alpha-hederin, beta-hederin and hederacolchiside A1, as compared to their action on mammalian cells cultured in vitro.

The in vitro antileishmanial activity of three saponins isolated from ivy, alpha-hederin, beta-hederin and hederacolchiside A1, was investigated on Leishmania infantum. The assessment of possible targets (membrane integrity, membrane potential, DNA synthesis and protein content) was performed in both Leishmania promastigotes and human monocytes (THP1 cells). Results observed in Leishmania showed that the saponins exhibited a strong antiproliferative activity on all stages of development of the parasite by altering membrane integrity and potential: hederacolchiside A1 appeared to be the most active compound against both promastigotes and amastigotes. Results observed in THP1 cells demonstrated that the saponins exerted also a potent antiproliferative activity against human monocytes, by producing a significant DNA synthesis inhibition. The ratio between antileishmanial activity on amastigotes and toxicity to human cells suggested that the saponins could be considered as possible antileishmanial drugs.

Animals↗
PubMed1999

The protective activity of alpha-hederine against H2O2 genotoxicity in HepG2 cells by alkaline comet assay.

This study was designed to evaluate the protective effect of alpha-hederine (alpha-hed) against H2O2-mediated DNA damage on HepG2 cell line by the alkaline comet assay. For the protective effect of alpha-hed study, cells were treated according to three protocols: pre-treatment, simultaneous treatment and post-treatment. The effect of alpha-hed on catalase activity was evaluated after treating the cells with 3.36 mg/ml of 3-amino-1,2,4-triazole (AMT) singly or in combination with alpha-hed (1.5 or 3 microg/ml) and H2O2 (8.8 microM) during 1 h. The catalase activity was also biochemically measured after treating cells with alpha-hed at 1.5, 3, or 15 microg/ml during 1 h. Additionally, the influence of alpha-hed on membrane RedOx potential, pool of reduced glutathione and total protein content was evaluated by flow cytometry. In the pre-treatment, the two concentrations of alpha-hed (1.5 and 3 microg/ml) decreased the lesions induced by H2O2 (8.8 microM) significantly. This decrease was about 57.2% and 66.1%, respectively. Similar results were observed when cells were treated with alpha-hed and H2O2 simultaneously. The decrease of H2O2-induced lesions was about 78.2% and 83.2% (alpha-hed 1.5 and 3 microg/ml, respectively). In the post-treatment protocol, this decrease was not significant. The combination of AMT and H2O2 induced more DNA damage than H2O2 alone (tail moment (TM) means was 31.4% and 21.8%, respectively). When alpha-hed was added to this mixture, TM means were reduced significantly (17.4% for alpha-hed 1. 5 microg/ml and 15.5% for alpha-hed 3 microg/ml). Up to 6.9 microg/ml, alpha-hed enhanced catalase activity (60.5%), followed by a decrease of the activity. Total protein content and membrane RedOx potential were slightly increased up to 11 microg/ml (14% and 3.6%, respectively) followed by a drop and a plateau. Pool of reduced glutathione remained unchanged up to 10 microg/ml then dropped and reached a plateau. In conclusion, alpha-hed could exert its protective effect against H2O2-mediated DNA damage by scavenging free radicals or by enhancing the catalase activity.

Catalase↗
PubMed1999

Pigment epithelium-derived factor protects cultured retinal neurons against hydrogen peroxide-induced cell death.

Pigment epithelium-derived factor (PEDF) is a neurotrophic protein synthesized and secreted by retinal pigment epithelial (RPE) cells in early embryogenesis and has been shown to be present in the extracellular matrix between the RPE cells and the neural retina. It induces neuronal differentiation and promotes survival of neurons of the central nervous system from degeneration caused by serum withdrawal or glutamate cytotoxicity. Because the role of PEDF in the retina is still unknown, we examined its ability to protect cultured retinal neurons against hydrogen peroxide (H(2)O(2))-induced cell death. Retinas of 0-2-day-old Sprague-Dawley rats were isolated and dissociated, and the neurons were maintained for 2 weeks in a synthetic serum-free medium. Immunocytochemical labeling showed that 50-60% of the cultured cells were rod photoreceptors. Treatment with H(2)O(2) induced significant death of retinal neurons in a dose- and time-dependent manner. Pretreatment with PEDF prior to insult greatly attenuated H(2)O(2)-induced cytotoxicity, and its effect was shown to be dose dependent. Cytotoxicity was determined by 3,(4,5-dimethylthiazol-2-yl)2, 5-diphenyl-tetrazolium bromide and lactate dehydrogenase assays, and apoptotic cell death was evaluated by the TdT-mediated digoxigenin-dUTP nick-end labeling assay. The present study also showed that H(2)O(2)-induced retinal neuron death was by apoptosis that could be inhibited by PEDF. Combination of PEDF with basic fibroblast growth factor, brain-derived neurotrophic factor, or ciliary neurotrophic factor improves the protection. These data strongly suggest that PEDF is a potential neuroprotective agent in the treatment of retinal degeneration.

Animals↗
PubMed1999

Unique retina cell phenotypes revealed by immunological analysis of recoverin expression in rat retina cells.

Among retina-specific proteins, recoverin is unique with respect to its cellular regulation in that it is found in rods, cones, some bipolar cells, and a rare population of cells in the ganglion cell layer. Recoverin is a calcium-binding protein which inhibits rhodopsin kinase from phosphorylating rhodopsin. Because cells in the inner layers of the retina do not contain rhodopsin kinase, arrestin, or other phototransduction proteins, it seems likely that recoverin has a different function in those cell types. To study this protein more fully, antibodies were generated against the entire mouse recoverin protein, as well as against peptides from the amino and from the carboxyl termini. These antibodies confirmed the localization of recoverin in vivo and clearly demonstrated, in culture, cells which were recoverin positive and rhodopsin negative. Surprisingly, two unique cell phenotypes were seen in cell culture which are not found in vivo. These cells are [rhodopsin(+), recoverin(-)] and [arrestin(+), recoverin(-)]. These phenotypes appear to represent the same population of cells and suggest that the recoverin gene can be regulated independent of genes for other phototransduction proteins. This cell culture system will be useful for investigating environments and factors which participate in the expression of the recoverin gene, and may identify regulatory features of the recoverin gene which cause it to be illicitly expressed in small-cell lung carcinomas in cancer-associated retinopathy (CAR).

Amino Acid Sequence↗