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Biomedical subjects

R Rodríguez

Publications and source records attributed to R Rodríguez.

At least 55 records · Page 3Linked to original sources
PubMed2002

Analysis of thiabendazole and procymidone in fruits and vegetables by capillary electrophoresis-electrospray mass spectrometry.

A capillary electrophoresis-mass spectrometry method for determining procymidone and thiabendazole in apples, grapes, oranges, pears, strawberries and tomatoes is described. Separation is achieved using a buffer of formic acid-ammonium formate at pH 3.5 with 2% of methanol. Fungicide residues present in the sample are preconcentrated by both solid-phase extraction and injection of large sample volumes into the capillary by a stacking technique, to obtain lower detection limits. Ionization is performed at atmospheric pressure in an electrospray type source and detection is carried out using positive ionization and selected ion monitoring modes. The quantitation limits are 0.005 and 0.05 mg kg(-1), and the mean recoveries are 64 and 75% for thiabendazole and procymidone, respectively, with relative standard deviations below 12% (n=5). Real fruit and vegetable samples are analyzed by the proposed method showing that residues of both fungicides are frequently present.

Bridged Bicyclo Compounds↗
PubMed2002

Allergenic diversity of the olive pollen.

A great number of allergenic proteins have been detected in olive pollen extracts. To date, nine allergens have been isolated and characterized, which have been called Ole e 1 to Ole e 9. The most prevalent olive allergen is Ole e 1, which affects more than 70% of patients hypersensitive to olive pollen, but others, such as Ole e 2, Ole e 8, and Ole e 9, have been demonstrated to be major allergens, and Ole e 6 or Ole e 7 reach high values of clinical incidence. Many of these allergens, such as Ole e 2 (profilin) and Ole e 3 (polcalcin), are involved in cross-reactivities, which agrees with their adscription to panallergenic families. Among the many olive allergens of high molecular mass, only Ole e 9 (46 kDa) has been characterized. The allergen is a polymorphic and glycosylated beta-1,3-glucanase, which belongs to a pathogenesis-related (PR-2) protein family. In addition to the polypeptide epitopes, Ole e 1 also exhibits IgE-binding determinants in the carbohydrate, which are recognized by more than 60% of the sera from patients sensitive to the whole allergen, although the level of such glycan-specific IgE seems not to be clinically relevant in the overall content of the sera. Recent advances in the elucidation of the structure of the Ole e 1-oligosaccharide component allows us to explain the antigenicity of the molecule. Finally, the recombinant production of several allergens from olive pollen in both bacterial and eukaryotic cells has allowed us to resolve problems derived from the polymorphism and scarcity of the natural forms of these allergens. The biological equivalence between the natural and recombinant forms lets us initiate studies on the design of mixtures for clinical purposes, in which hypoallergenic derivatives of these allergens could play a definitive role.

Allergens↗
PubMed2002

Olive allergen-specific IgE responses in patients with Olea europaea pollinosis.

BACKGROUND: Olive tree (Olea europaea) pollen is an important cause of pollinosis in the countries of the Mediterranean area. OBJECTIVE: This work aimed to study the IgE-binding frequency of Ole e 1, Ole e 2, Ole e 3, Ole e 6 and Ole e 7 from O. europaea pollen in a large population of olive pollen-allergic patients. METHODS: We studied: 119 consecutive patients with seasonal rhinitis and/or asthma and a positive skin prick test to O. europaea pollen extract; 10 atopic patients without history of pollinosis and a negative skin prick test to O. europaea; and 10 healthy controls. Allergens were purified from O. europaea pollen extract by reverse phase HPLC and characterized by N-terminal amino acid sequencing, MALDI analysis, and specific IgE immunodetection. Skin prick tests and ELISA titration against above mentioned purified olive pollen allergens were performed in all pollinic patients and controls. RESULTS: One-hundred and seven (90.7%) patients had a positive skin response to Ole e 1; 88 (74.6%) reacted to Ole e 2; 57 (47.9%) reacted to both Ole e 6 and Ole e 7; and 43 (37.8%) reacted to Ole e 3. The allergenic activity determined by ELISA to Ole e 1 was found in 84%; to Ole e 2 in 61.3%; to Ole e 3 in 31.9%; to Ole e 6 in 39.4%; and to Ole e 7 in 41.2% of patients. All patients had positive skin responses to at least one of the allergens tested, However, a combination of Ole e 1 and Ole e 2 together with a minor allergen Ole e 6 or Ole e 7, disclosed the same diagnostic value that was obtained with the use of crude olive pollen extract. The nonatopic and atopic control subjects did not react to any purified allergens on the skin prick test. CONCLUSIONS: These results indicate that Ole e 1 and Ole e 2 are major allergens in patients with O. europaea pollinosis in our population. A combination of a few olive pollen allergens can substitute the crude extract for in vivo as well as in vitro diagnostic purposes.

Adult↗
PubMed2002

Allergy after ingestion or inhalation of cereals involves similar allergens in different ages.

BACKGROUND: Cereals are among the major foods that account for food hypersensitivity reactions. Salt-soluble proteins appear to be the most important allergens contributing to the asthmatic response. In contrast, very limited information is available regarding cereal allergens responsible for allergic reactions after ingestion of cereal proteins. OBJECTIVE: The aim of this study was to evaluate the allergenic reactivity of ingested and inhaled cereal allergens in different ages, in order to investigate if the response to different allergens would depend on the sensitization route. METHODS: We included 66 patients in three groups. Group 1: 40 children aged 3 to 6 months who suffered from diarrhoea, vomiting, eczema or weight loss after the introduction of cereal formula in their diet and in which a possibility of coeliac disease was discarded. Group 2: 18 adults with food allergy due to cereals tested by prick tests, specific IgE and food challenge. Group 3: eight patients previously diagnosed as having baker's asthma. Sera pool samples were collected from each group of patients and IgE immunoblotting was performed. RESULTS: We found an important sensitization to cereal in the 40 children. The most important allergens were wheat followed by barley and rye. Among the adults with cereal allergy, sensitization to other allergens was common, especially to Lolium perenne (rye grass) pollen. Immunoblotting showed similar allergenic detection in the three groups. CONCLUSION: Clinically significant reactivity to cereal may be observed in early life. Inhalation and ingestion routes causing cereal allergy seem to involve similar allergens. The diet control was more effective in children. The possibility of cereal allergy after the introduction of cereal formula during the lactation period should not be underestimated.

Administration, Inhalation↗
PubMed2002

Are Ca2+-binding motifs involved in the immunoglobin E-binding of allergens? Olive pollen allergens as model of study.

BACKGROUND: Several Ca2+-binding proteins, which possess EF-hand sites with a high sequence similarity, have been found to be able to induce Type-I allergy. OBJECTIVE: To study whether the common EF-hand sequential motifs can be involved in the IgE-reactivity of these proteins, thus being responsible of a degree of cross-reactivity among different Ca2+-binding proteins. METHODS: Two olive pollen allergens, Ole e 3 and Ole e 8, have been used in the study. Parvalbumin and calmodulin were included in immunological analyses. Sera from patients allergic to olive pollen, as well as Ole e 3- and Ole e 8-specific rabbit antisera were used in indirect enzyme-linked immunosorbent assay (ELISA), ELISA inhibition assays and immunoblotting. Conformational analyses (circular dichroism spectra and thermal stability) and specific immunodetection assays were performed in the presence and the absence of Ca2+. Chemical breakdown and high-performance liquid chromatography (HPLC) was used to obtain fragments from Ole e 3 containing a single EF-hand motif. RESULTS: Thirty-four (17%) and 16 (8.2%) out of 195 sera from patients allergic to olive pollen contained specific IgE against Ole e 3 and Ole e 8, respectively. The IgE-binding of 12 allergic sera diminished up to 22% for Ole e 3 and to 82% for Ole e 8, when depleted Ca2+. A pool of these sera recognized the two olive allergens and parvalbumin, but at very different extent. Inhibition of the IgE-binding was only achieved between two olive allergens. No structural relationships between Ole e 3 and Ole e 8 were established when specific polyclonal antisera against both proteins were used. CONCLUSION: EF-hand Ca2+-binding sites can not be considered as general allergenic motifs responsible for the cross-reactivity between Ca2+-binding allergens. Different families of Ca2+-binding allergens have specific epitopes that could be involved in the cross-reactivity among members of the same family.

Adolescent↗
PubMed2002

Double dimer peptide constructs are immunogenic and protective against Plasmodium falciparum in the experimental Aotus monkey model.

Multiple antigen peptide constructs (MAPs) have been used to obtain defined multimeric peptide molecules useful in the development of possible synthetic malaria vaccines. In this context, a method was developed, named double dimer constructs (DDCs), involving the direct synthesis of a dimeric peptide with a C-terminal cysteine. A tetrameric molecule was then obtained by oxidation of sulfhydryl groups. Dimer synthesis was optimized using a Fmoc/tBu strategy, dimers were purified by HPLC, oxidized with DMSO and characterized by HPLC and MALDI-TOF-MS. The tetramers or DDCs obtained by this method were used as immunogens in the search for a possible malaria vaccine. It was found that they were immunogenic in the experimental Aotus monkey model, and were able to induce protective immunity when challenged experimentally with a highly infective Plasmodium falciparum malaria strain.

Amino Acid Sequence↗
PubMed2002

Evaluation of the peripheral dose to uterus in breast carcinoma radiotherapy.

The absorbed dose outside of the direct fields of radiotherapy treatment (or peripheral dose, PD) is responsible for radiation exposure of the fetus in pregnant women. Because the radiological protection of the unborn child is of particular concern in the early period of the pregnancy, the aim of this study is to estimate the PD in order to assess the absorbed dose in the uterus in a pregnant patient irradiated for breast carcinoma therapy. The treatment was simulated on an Alderson-Rando anthropomorphic phantom, and the radiation dose to the fetus was measured using an ionisation chamber and thermoluminescence dosemeters. Two similar treatments plans with and without wedges were delivered, using a 6 MV photon beam with two isocentric opposite tangential fields with a total dose of 50 Gy, in accordance with common established procedures. Average field parameters for more than 300 patients were studied. Measurements showed the fetal dose to be slightly lower than 50 mGy, a level at which the risk to the fetus is uncertain, although several authors consider this value as the dose threshold for deterministic effects. The planning system (PS) underestimated PD values and no significant influence was found with the use of wedge filters.

Breast Neoplasms↗
PubMed2002

Olive pollen allergen Ole e 8: identification in mature pollen and presence of Ole e 8-like proteins in different pollens.

In a first approach, Ole e 8, a novel Ca2+-binding protein from olive pollen, was cloned and produced in Escherichia coli. We have obtained the natural form of Ole e 8 (nOle e 8) from the pollen and examined its immunologic equivalence with its recombinant form (rOle e 8). Size exclusion chromatography and a phenyl-Sepharose CL-4B affinity column were used to obtain nOle e 8 from the olive pollen. Inhibition assays by immunoblotting, using rOle e 8-specific rabbit antiserum, were performed to analyze the immunologic equivalence between the natural and the recombinant allergen, as well as to detect its presence in other pollens. Recombinant and natural Ole e 8 resulted immunologically equivalents, since they completely inhibited the IgG binding of the polyclonal antiserum to each other. Ole e 8-like proteins were detected in Oleaceae and Juniperus communis pollen, and might contribute to cross-reactivity processes between taxonomically related pollens.

Allergens↗
PubMed2001

Analysis of post-harvest fungicides by micellar electrokinetic chromatography.

A method based on solid-phase extraction (SPE) and micellar electrokinetic chromatography (MEKC) was developed for the simultaneous determination of carbendazim, imazalil, methylthiophanate, O-phenylphenol, prochloraz, procimidone, thiabendazole and triadimefon residues in grape, lettuce, orange and tomato. Selectivity and resolution were studied changing the pH and the concentration of the buffer, the type and concentration of surfactant and the methanol content in the mobile phase. A buffer consisting of 4 mM borate with 75 mM sodium cholate (pH 9.2) gave the best results. The recoveries of the fungicides in spiked fruit and vegetable samples ranged from 30 to 105%, and the limits of detection were between 0.1 and 1 mg kg(-1). The reproducibility and repeatability of the combination of SPE pretreatment and MEKC were good for all the compounds, except for imazalil and O-phenylphenol in oranges, due to some matrix compounds interfering with the separation. The method was applied to post harvest treated samples, and the fungicides were sometimes detected at concentration levels lower than maximum residue limits (MRLs).

Buffers↗
PubMed2001

Ole e 9, a major olive pollen allergen is a 1,3-beta-glucanase. Isolation, characterization, amino acid sequence, and tissue specificity.

Olive pollen allergy is a clinical disorder affecting the human population of Mediterranean areas. A novel major allergen, Ole e 9, has been isolated from olive pollen by gel permeation, hydrophobic affinity, and reverse-phase high performance liquid chromatographies. It is involved in the allergic responses of 65% of patients suffering olive pollinosis. Ole e 9 (molecular mass of 46.4 kDa) displays 1,3-beta-endoglucanase activity (38.9 +/- 5.6 mg of glucose released/min x micromol of protein at pH 4.5-6.0 using laminarin as substrate). It is the first 1,3-beta-glucanase, a member of the "pathogenesis-related" protein family, detected in pollen tissue. Seven tryptic peptides of the allergen were sequenced by Edman degradation and used for designing primers to clone the cDNA codifying the protein. Specific cDNA for Ole e 9 was synthesized from total RNA and amplified using the polymerase chain reaction. The allergen sequence showed an open reading frame of 460 amino acids comprising a putative signal peptide of 26 residues. It shows 39, 33, and 32% sequence identity including the catalytic residues when compared with 1,3-beta-glucanases from wheat, willow, and Arabidopsis thaliana, respectively. Northern blot analysis showed that Ole e 9 transcript is specifically expressed in the pollen tissue, and highly conserved counterparts were only detected in taxonomically related pollens.

Allergens↗
PubMed2001

Liquid chromatographic-mass spectrometric determination of post-harvest fungicides in citrus fruits.

Liquid chromatography (LC)-atmospheric pressure ionisation (API)-mass spectrometry (MS) has been used to determine residues of five fungicides in oranges with a minimum sample cleanup. Atmospheric pressure chemical ionisation (APCI) and electrospray (ES) were compared and both gave similar results in terms of sensitivity and structural information. The main ions were [M+H]+ for carbendazim, imazalil, thiophanate methyl and thiabendazole, and [M+H-C4H9NHCO]+ for benomyl. Samples were extracted with sodium sulphate and ethyl acetate. Although benomyl and thiophanate methyl were transformed through the extraction procedure to carbendazim, the method showed good precision (<13%) and recovery (>70%), except for thiophanate methyl (50%), whilst also yielding limits of detection (<0.03 mg kg(-1)) that are adequate for the determination of the studied fungicides in oranges.

Atmospheric Pressure↗
PubMed2001

Phase II study of irinotecan as first-line chemotherapy for patients with advanced colorectal carcinoma.

BACKGROUND: The objective of this multicenter, open-labeled, Phase II study performed in Spain was to assess the efficacy and safety of irinotecan (CPT-11) as first-line chemotherapy for patients suffering from advanced colorectal carcinoma (CRC). METHODS: Patients with histologically proven CRC and at least one bidimensionally measurable lesion, ages 18-70 years, with a performance status < or = 2, normal analytical values, and no prior chemotherapy or only adjuvant chemotherapy completed before study entry were selected. The treatment schedule was CPT-11 350 mg/m(2) intravenously administered once every 3 weeks. Both tumor response and toxicity were assessed using the World Health Organization and National Cancer Institute common toxicity criteria. Changes in performance status, weight, and symptoms also were measured. RESULTS: Sixty-five patients (44 chemotherapy-naïve patients and 21 patients who completed prior adjuvant treatment) were enrolled. Of these, 24.7% of patients responded to the treatment, and 41.5% of patients had stable disease. Patients who had not received prior adjuvant chemotherapy had a lower rate of progression on therapy (27.3%) compared with those who had received prior adjuvant chemotherapy (42.9%). The median survival was 19.9 months (range, 0.3-29.3 months). No significant differences were found in the median survival between chemotherapy-naïve patients and patients who had received previous chemotherapy. Grade 3-4 diarrhea and neutropenia were the most frequent severe toxic events, which were observed in 23.1% and 30.8% of patients and in 5.9% and 10.9% of the cycles, respectively. CONCLUSIONS: The current antitumor efficacy results show that 350 mg/m(2) of CPT-11 administered every 3 weeks is an active and feasible first-line chemotherapy regimen for patients with CRC. Finally, the overall safety data confirmed that CPT-11 is a well tolerated treatment.

Adult↗
PubMed2001

Determination of urea-derived pesticides in fruits and vegetables by solid-phase preconcentration and capillary electrophoresis.

A multiresidue analytical method based on solid-phase extraction (SPE) enrichment combined with capillary electrophoresis (CE), using micellar electrokinetic capillary chromatography (MEKC), was developed to determine ten substituted urea pesticides in orange and tomato samples. Several factors such as pH, composition and concentration of the buffer, concentration of surfactant, addition of organic solvent, and working voltage were optimized to obtain the best compound separation in the shortest time. Separation can be achieved in 7 min using a micellar aqueous pH 9 buffer composed of 4 mM borate and 35 mM sodium dodecyl sulfate. After an SPE procedure, which provided a 10-fold enrichment, the limit of detection was about 0.05 mg kg(-1), which is in the order of the maximum residue limits (MRLs) established by the European Union (EU) for most of these compounds. Increasing the enrichment factor by using a larger amount of sample is difficult in oranges due to the matrix interferences, but is possible in tomatoes, which gave cleaner extracts and easily reached a 25-fold enrichment factor. The procedure involving SPE and CE provided acceptable recoveries (ranged 42-118%) and relative standard deviations (RSDs; < 19%) at levels between 0.3 and 5 mg kg(-1).

Electrophoresis, Capillary↗
PubMed2001

Steam-explosion of olive stones: hemicellulose solubilization and enhancement of enzymatic hydrolysis of cellulose.

Olive stones (whole stones and seed husks in fragments) were processed by steam-explosion under different experimental conditions of temperature and time, 200-236 degrees C for 2-4 min, with or without previous acid impregnation with 0.1%, H2SO4 (w/w). This paper examines the solubilization of hemicelluloses and their molecular weight distribution. The subsequent enzymatic hydrolysis of the solid residue, using a preparation of cellulase, was also studied. The maximum yield of the pentosan recovered in the water solution was 63% pentose in the starting material for seed husk treated at 200 degrees C for 2 min (log R0 3.24) prior to acid-impregnation, or at 215 degrees C for 2 min (log R0 3.69) without acid, compared to 39% of the potential yield for whole stones pre-impregnated with acid under more severe conditions (at log R0 = 4.07). This indicates that the autohydrolysis of hemicellulose in seed husks when compared to whole stones is enhanced. The molecular weight distribution of profile sugars showed that the depolymerization of hemicelluloses is a function of the severity of the treatment. Steam-explosion improved the accessibility of the cellulose and increased the enzymatic hydrolysis yield after steam-explosion with respect to material without steam explosion (ball-milled material), although little increase in the extent of saccharification occurred when the alkali-soluble lignin was removed. Only when the substrate was post-treated with Na-chlorite was the enzymatic hydrolysis improved, the water-insoluble residue being almost completely hydrolyzed in 8 h of incubation.

Atmospheric Pressure↗
PubMed2001

Rheological evaluation of the interactions between cationic celluloses and Carbopol 974P in water.

This paper reports on the influence of the structural properties of two cationic hydroxyethylecelluloses, polyquaternium-4 (PQ-4; 1.13-1.27% N) and polyquaternium-10 (PQ-10; 1.88-1.95% N), on the rheological behavior of their dispersions and of the dispersions of their blends with Carbopol 974P (60.9% COOH) in water. Dynamic shear oscillation measurements showed that the rheological behavior of 1 and 2% (w/w) cellulose polymers was mainly viscous. Flow curves of PQ-10 dispersions presented a higher consistency and pseudoplasticity than PQ-4 dispersions, in which the thixotropy was higher. Structural features, such as type and distribution of substituents and molecular weight, explain why they behave different. The presence of 0.00125-0.02% Carbopol in diluted cationic cellulose (0.01-0.08%) dispersions produced an important decrease in viscosity, due to a strong associative process via an electrostatic interaction phenomenon. Similar results were obtained when sodium acetate was added instead of Carbopol. In contrast, in the concentrated range (1% cellulose polymer), the viscous (G") and especially the elastic (G') moduli of the dispersions increased monotonically with Carbopol concentration (0.010-0.125%) and became physical gels, except in the proximity of the neutralization of the ammonium groups (0.07% Carbopol for PQ-4, and 0.1% Carbopol for PQ-10) in which G" and G' decreased. The concentrated dispersions showed pH-sensitivity when the Carbopol added was around or above the neutralization point. In dispersions with this composition, consistency increased dramatically when pH changed from 4.5 to 7.4. This property can open a wide range of applications, especially in the pharmaceutical field to prepare gelling in situ systems.

Acrylates↗