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Biomedical subjects

R Aragón

Publications and source records attributed to R Aragón.

17 recordsLinked to original sources
PubMed2001

Antiprotozoal activities of Colombian plants.

In our search for therapeutical alternatives for antiprotozoal chemotherapy, we collected a selection of 44 plants from western Colombia upon ethnopharmacological and chemotaxonomic considerations. Polar and apolar extracts of these species were examined for antimalarial activity using in vitro tests with two clones of Plasmodium falciparum. Leishmanicidal and trypanocidal activity were determined in vitro using promastigote and amastigote forms of several strains of Leishmania sp. and epimastigotes of Trypanosoma cruzi. Among the selected plants, the 15 following species showed good or very good antiprotozoal activity in vitro: Aspidosperma megalocarpon, Campnosperma panamense, Conobea scoparioides, Guarea polymera, Guarea guidonia, Guatteria amplifolia, Huberodendron patinoi, Hygrophila guianensis, Jacaranda caucana, Marila laxiflora, Otoba novogranatensis, Otoba parviflora, Protium amplium, Swinglea glutinosa and Tabernaemontana obliqua. Cytotoxicity was assessed in U-937 cells and the ratio of cytotoxicity to antiprotozoal activity was determined for the active extracts. Ten extracts from eight species showed selectivity indexes > or = 10. Among the extracts that showed leishmanicidal activity, the methylene chloride extract of leaves from C. scoparioides showed a selectivity index in the same range that the one of the Glucantime control. Several of the active leishmanicidal plants are traditionally used against leishmaniasis by the population of the concerned area.

Animals↗
PubMed2001

Triterpenoid saponins from Isertia pittieri.

Two new 27-nor-triterpenoid saponins, pyrocincholic acid 3 beta-O-beta-D-quinovopyranosyl-28-[beta-D-glucopyranosyl(1-->6)-beta-D-glucopyranosyl] ester (1) and pyrocincholic acid 3 beta-O-beta-D-quinovopyranosyl(1-->6)-beta-D-glucopyranosyl-28-[beta-D-glucopyranosyl(1-->2)-beta-D-glucopyranosyl] ester (2) were isolated from the stem bark of Isertia pittieri, together with two known bidesmosidic quinovic acid glycosides. The structures of 1 and 2 were determined on the basis of spectroscopic studies.

Chromatography, High Pressure Liquid↗
PubMed1999

Specific interactions of monotetrahydrofuranic annonaceous acetogenins as inhibitors of mitochondrial complex I.

Annonaceous acetogenins (ACG) are a wide group of cytotoxic compounds isolated from plants of the Annonaceae family. Some of them are promising candidates to be a future new generation of antitumor drugs due to the ability to inhibit the NADH:ubiquinone oxidoreductase of the respiratory chain (mitochondrial complex I), main gate of the energy production in the cell. ACG are currently being tested on standard antitumor trials although little is known about the structure activity relationship at the molecular level. On recent studies, the relevance of several parts of the molecule for the inhibitory potency has been evaluated. Due to the great diversity of skeletons included in this family of natural products, previous studies on the presence and distribution of oxygenated groups along the alkyl chain only covered the compounds with different bis-tetrahydrofuranic (bis-THF) relative configurations. Therefore, we have investigated the inhibitory action of all the mono-tetrahydrofuranic (mono-THF) acetogenins available, which differ in the oxygenated arrangements along the molecule. Our results show that the hydroxyl and carbonyl groups, placed in the aliphatic chain that links the initial gamma-lactone moiety with the dihydroxylated tetrahydrofuranic ring system, significantly contribute for modulating the inhibitory potency of the ACG through specific effects.

Animals↗
PubMedDate not supplied

Phenotypes of alpha-1-antitrypsin in intrinsic asthma and ASA-triad patients.

The frequency of presence of various phenotypes of alpha 1-antitrypsin was studied in 31 patients with intrinsic asthma and 11 with ASA-Triad, and compared to a group of 200 people representative of the general population. The MZ and SZ phenotype is more frequent in intrinsic asthmatics (p < 0.00001) and MZ in ASA-Triad (p < 0.0005) than in the control group. No differences were found between the intrinsic asthmatics and ASA-Triad. All the patients were divided into groups according to their clinical characteristics and an increase of the MZ phenotype was observed (p < 0.001) in patients with: nasal polyposis, intolerance to non-steroidal anti-inflammatories, a family history of atopy and peripheral eosinophilia (p < 0.01). Alpha-1-antitrypsin deficiency could be important in the pathogenesis of inflammatory processes and in the clinical manifestations characteristic of patients with intrinsic asthma and ASA-Triad.

Adult↗
PubMedDate not supplied

[Allergic rhinitis in the region of Mérida].

We studied the whole of 3,047 patients who consult our unit because of a presumable allergic affection. The 20% to suffer from allergic rhinitis. The most frequent clinical presentation has been rhinitis allergic seasonal followed by perennial and to extend seasonal. We have diagnosed through by prick-test, specific IgE and ocular provocation test. The ethiology more common has been the grass pollen together olive followed pollen grass from seasonal rhinitis. The mites dust from perennial rhinitis and the grass and polisensitizations to seasonal extend.

Adolescent↗
PubMedDate not supplied

Serum immunoglobulin E levels in relation to adenoid surgery.

The adenoid tissue is an immunecompetent lymphoid organ, which has the capacity of reacting against numerous antigens. We have studied the influence that the elimination of the said tissue would have on the total IgE serum levels in 33 patients of an average age of 5 and criteria of adenoidectomy and in whom these levels were measured before and after surgery. We have not noticed any statistically significant differences in the IgE values after adenoidectomy with respect to those prior to surgery, which were normal. Adenoidectomy, like other authors have observed after tonsillectomy, does not alter the IgE serum values.

Adenoidectomy↗