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Biomedical subjects

R Rodríguez

Publications and source records attributed to R Rodríguez.

At least 73 records · Page 4Linked to original sources
PubMed2001

Olive fruit cell wall: degradation of pectic polysaccharides during ripening.

Olive fruits at three stages of ripening (green, cherry, and black) have been studied. After cell wall isolation, the compositions of the cell wall and that of the phosphate-soluble polysaccharides were determined. In cell walls, decreases in arabinose, xylose, glucose, and uronic acid levels were observed, together with a slight increase in mannose on ripening. At the beginning of ripening, fragments of pectic polymers were the major constituents of the phosphate-soluble fraction, with the hemicellulosic ones increasing toward the end of the process. The molecular weight of the fragments solubilized was approximately 6 kDa. After cell wall fractionation, the pectic polysaccharides soluble in imidazole and sodium carbonate were also studied. In both fractions, between the green and cherry stages of ripening, a significant loss of homogalacturonans took place. Between the cherry and black stages of ripening, rhamnogalacturonan side chains were also released in addition to homogalacturonans. In any of the pectic fractions, changes in apparent molecular weight were quantified.

Arabinose↗
PubMed2001

Olive fruit cell wall: degradation of cellulosic and hemicellulosic polysaccharides during ripening.

Cellulose and hemicelluloses obtained from the cell walls of partially depectinated olives have been studied at three stages of ripening (green, cherry, and black). Hemicelluloses were fractionated into two groups, the amounts of which diminished during ripening: those soluble in 4% KOH diminished between the cherry and black stages, whereas those soluble in 24% KOH did so between the green and cherry stages. Arabinoxylans, xyloglucans, and homo- and/or rhamnogalacturonans to a lesser extent were present in these fractions. After ion exchange and size exclusion chromatographies, decreases in the molecular weights of hemicelluloses, mainly in the neutral fractions, were observed. The amount of cellulose also decreased, but at the second stage of the ripening process. Approximately 2 mg/fruit of glucose was lost from cellulose, and the amount of uronic acids increased (0.23 mg/fruit).

Cell Wall↗
PubMed2001

Capillary zone electrophoresis for the determination of thiabendazole, prochloraz and procymidone in grapes.

Capillary zone electrophoresis with UV detection was applied to the simultaneous determination of thiabendazole, prochloraz and procymidone in grapes. Electrolyte conditions such as pH, composition and concentration of the buffer, addition of organic solvent and working voltage were checked to obtain a high-performance separation of the three fungicides (by measurement of separation efficiency and resolution). The most critical parameter was the pH of the running buffer. The best separation was achieved in 4 mM phosphate solution at pH 3.5. The repeatability of the migration times, expressed as RSD, was < 0.44%. The three peaks were completely resolved with a separation efficiency up to 100,000 theoretical plates. Solid-phase extraction was used for the isolation and preconcentration of the fungicides, which provided a concentration factor of 10:1 and limits of detection lower than the maximum residue limits. The mean recoveries of the fungicides were 73.75% for thiabendazole, 41.70% for prochloraz and 92.23% for procymidone. This method was used to determine these compounds in 20 real samples taken from a local market.

Bridged Bicyclo Compounds↗
PubMed2001

Immunological and molecular characterization of the major allergens from lilac and privet pollens overproduced in Pichia pastoris.

The main allergens from privet and lilac pollens, Lig v 1 and Syr v 1, are proteins homologous to Ole e 1 and have been shown to be involved in cross-reactivity. To overproduce the correctly folded Lig v 1 and Syr v 1 allergens and to study their immunological properties in comparison with those of their natural counterparts. The yeast Pichia pastoris was used as an expression system to produce these recombinant allergens. The proteins were isolated by ion-exchange and size-exclusion chromatographies. Amino acid quantifying, Edman degradation, mass spectrometry and circular dichroism were carried out to obtain molecular properties of the recombinant proteins. Anti-Ole e 1 monoclonal and polyclonal antibodies, as well as sera from patients allergic to olive pollen, were used in immunoblotting and ELISA for immunological characterization. Recombinant Lig v 1 and Syr v 1 were secreted at high yield to the extracellular medium of the yeast. The purified proteins displayed the native conformation, as deduced from their spectroscopic properties and binding ability to an IgG monoclonal antibody. The recombinant allergens behaved similarly to their natural counterparts when they were analysed against Ole e 1-specific antibodies. IgE and IgG binding properties of lilac and privet allergens to olive allergic sera and Ole e 1-specific antibodies indicated that these molecules share common B-cell epitopes with Ole e 1. P. pastoris yeast is an appropriate system for the efficient production of Ole e 1-like allergens, which could be used as analogous allergens and predictors of clinical sensitization.

Allergens↗
PubMed2001

The spectrum of olive pollen allergens.

Olive pollen is one of the most important causes of seasonal respiratory allergy in Mediterranean countries, where this tree is intensely cultivated. Among the high number of protein allergens detected in this pollen, 8 - Ole e 1 to Ole e 8 - have been isolated and characterized. Ole e 1 is the most frequent sensitizing agent, affecting more than 70% of the patients suffering of olive pollinosis, although others, such as Ole e 4 and Ole e 7, have also been shown to be major allergens. In this context, the prevalence of many olive pollen allergens seems to be dependent on the geographical area where the sensitized patients live. Some of the olive allergens have been revealed as members of known protein families: profilin (Ole e 2), Ca(2+)-binding proteins (Ole e 3 and Ole e 8), superoxide dismutase (Ole e 5) and lipid transfer protein (Ole e 7). No biological function has been demonstrated for Ole e 1, whereas Ole e 4 and Ole e 6 are new proteins without homology to known sequences from databases. cDNAs encoding for Ole e 1, Ole e 3 and Ole e 8 have been overproduced in heterologous systems. The recombinant products were correctly folded and exhibited the functional activities of the natural allergens. In addition to the Oleaceae family, other species, such as Gramineae or Betulaceae, contain pollen allergens structurally or immunologically related to those of the olive tree. This fact allows to detect and evaluate antigenic cross-reactivities involving olive allergens. The aim of this research is the development of new diagnostic tools for olive pollinosis and new approaches to improve the classical immunotherapy.

Allergens↗
PubMed2001

[The efficacy and safety of continuous epidural analgesia versus intradural-epidural analgesia during labor].

OBJECTIVE: To determine the efficacy and safety of intradural-epidural analgesia in comparison with continuous epidural analgesia during labor and childbirth. PATIENTS AND METHOD: Forty-two women whose labor began spontaneously were enrolled and distributed randomly in two groups. The intradural-epidural analgesia group (IEA, n = 21) received 25 microgram of intradural fentanyl with 2.5 mg of isobaric bupivacaine with adrenalin, after which analgesia was maintained with epidural administration of one 8 mL bolus of 0.125% bupivacaine, followed by perfusion of a balanced concentration at a rate of 8 ml/h. Patients in the continuous epidural analgesia group (CEA, n = 21) were given 8 ml of 0.25% bupivacaine with adrenalin; the epidural perfusion of 0.125% bupivacaine and 1 microgram/ml of fentanyl was started at the same rate as in the IEA group. We recorded pain as assessed on a visual analog scale, extension of sensory and motor block, maternal hemodynamic constants, number of boluses of bupivacaine used, total doses of bupivacaine and oxytocin, instruments needed for childbirth, and side effects (pruritus, nausea and vomiting). RESULTS: Analgesic efficacy during the first 30 minutes was greater in the IEA group. The total dose of bupivacaine, required top-up boluses, and the extension of sensory block at 30 minutes, one hour and two hours were also significantly less in the IEA group. The incidence of pruritus was higher in the IEA group. No significant differences were observed for other variables. CONCLUSIONS: Intradural-epidural analgesia provides effective analgesia for labor, with rapid onset, reduced extension of sensory block, lower total doses of local anesthetics and few side effects.

Adult↗
PubMed2001

[Influence of bispectral index monitoring on fentanyl requirements during total intravenous anesthesia for major gynecological surgery].

OBJECTIVE: To determine the influence that bispectral index (BIS) monitoring of hypnosis might have on need for analgesia during surgery under total intravenous anesthesia provided by bolus administration of fentanyl. PATIENTS AND METHOD: Prospective, randomized and partially double-blind study of 40 patients undergoing major gynecological surgery under total intravenous anesthesia with propofol and fentanyl. In the BIS group (n = 20) propofol administration was adjusted to maintain BIS between 40 and 60. In the control group (n = 20) standard doses were given: 10 mg/kg-1/h-1 after anesthetic induction and for 5 minutes, 8 mg/kg-1/h-1 over the next 5 minutes and 6 mg/kg-1/h-1 throughout the rest of the operation. All patients received intravenous bolus administration of 150 or 75 microg of fentanyl to maintain analgesia whenever systolic blood pressure and heart rate increased 20% over baseline. We compared propofol and fentanyl requirements, intraoperative changes in BIS, and awakening from anesthesia. RESULTS: Patient and surgical characteristics were similar in both groups. BIS monitoring allowed propofol administration to be decreased a mean 24% during maintenance of anesthesia, and this in turn was associated with a significant increase in mean dose of fentanyl (415 microg versus 253 microg in the BIS and control groups, respectively; p = 0.01). Mean values of BIS were higher in the BIS group (46.4 versus 42.2; p = 0.04) and patients in the BIS group awoke sooner (in 7.7 min versus 11.1 min; p = 0.01) and tended to report less pain upon arrival at the postanesthetic recovery room, although the difference was not statistically significant. CONCLUSIONS: BIS monitoring of depth of hypnosis can influence requirements for fentanyl during total intravenous anesthesia by bolus dosing for maintenance of analgesia. This is probably due to changes in the administration of propofol made possible by BIS monitoring.

Adult↗
PubMed2001

[Characterization of the expression and function of SigM an ECF sigma factor in mycobacteria].

The survival of M. tuberculosis within the macrophage depends on its ability to respond to oxidative stress, and the ECF subfamily of sigma factors likely play an important role. We studied SigM, a sigma factor whose gene is located near the origin of DNA replication. In both M. smegmatis and M. bovis BCG, the expression of sigM was induced at high temperature and in stationary phase. Mutants of M. smegmatis without an intact sigM were defective for survival in oxidative stress and also for the induction of thioredoxin reductase activity in oxidative stress. The thioredoxin system reduces disulfide bonds that are formed in oxidative stress. SigM thus appears to regulate thioredoxins and forms part of the bacteria's complex protective responses.

DNA Replication↗
PubMed2000

Cloning, expression and characterization of a novel four EF-hand Ca(2+)-binding protein from olive pollen with allergenic activity.

A novel allergenic member of the family of Ca(2+)-binding proteins has been cloned from olive tree pollen. The isolated DNA codes for a protein of 171 amino acid residues, which displays four EF-hand sequence motifs. The encoded protein was overproduced in Escherichia coli and purified. The protein (18¿ omitted¿795 Da), which binds Ca(2+) and IgE antibodies from patients allergic to olive pollen, undergoes Ca(2+)-dependent conformational changes. It is retained on a phenyl-Sepharose column, which indicates the existence of regulatory EF-hand domains. This fact suggests its involvement in Ca(2+)-dependent signal transduction events of the pollen grain. This allergen could be considered as a member of a new subfamily of EF-hand Ca(2+)-binding proteins since it displays a low amino acid sequence similarity with the so far known proteins.

Allergens↗
PubMed2000

Apatite growth on calcium adsorbed surface of wet flocculated silica particles immersed in a modified simulated body fluid.

An alternative method for the calcium phosphate apatite formation onto the surface of flocculated pure silica particles is reported, in an attempt to understand the possible mechanism for the apatite formation. A stable silica sol was flocculated by adding calcium ions in aqueous solution. The wet flocks were resuspended in a basic aqueous solution containing a calcium salt, trying to allow the absorption of calcium ions onto the silica surface through a hydrogen ion exchange. The as-prepared materials were immersed in a modified simulated body fluid at different temperatures (37 and 90 degrees C) and silica concentrations. It was found that these factors have a strong influence on the apatite formation. The apatite formation was confirmed by (31)P MAS-NMR, FT-Raman, XRD, and TEM.

Adsorption↗
PubMed2000

Rapid quantification of DNA methylation by high performance capillary electrophoresis.

The actual methods to evaluate total DNA methylation based on high performance liquid chromatography (HPLC) are long and tedious due to the specific running buffers required. In this work, a new open-tube capillary electrophoresis system has been applied to the separation of acid hydrolyzed genomic DNA and so, to the evaluation of genomic DNA methylation. Several running conditions were tested but separation of cytosine and 5-methyl-cytosine was only possible by sodium dodecyl sulfate (SDS) micelle system. The importance of sample dissolution preparation has also been demonstrated. The results of this study open up the possibility of quantification of the relative methylation degree of rapid genomic DNA by a simple method based on high performance capillary electrophoresis (HPCE).

DNA Methylation↗
PubMed2000

Chemical characterization of asturian cider.

Ninety-four samples of Asturian natural cider were analyzed for titratable and volatile acidities, pH, alcoholic, total polyphenol, and acidic polysaccharide contents, nonvolatile acids, polyalcohols, residual sugars, and major volatile compounds. A partial least-squares regression analysis (PLR-1) was performed to correlate the chemical composition and the origin of the raw material, the cider samples being grouped into two categories: an "odd" class, cider made from foreign apples (1995 and 1997), and an "even" class, ciders made from Asturian apples (1996 and 1998). The mathematical model has a multiple linear correlation coefficient of 80%.

Alcohols↗
PubMed2000

Allergenic cross-reactivity of olive pollen.

BACKGROUND: Sera of patients allergic to olive (Olea europaea) pollen were used to analyze the IgE cross-reactivity between olive-pollen extract and other pollens obtained from phylogenetically unrelated species. METHODS: We used IgE immunostaining of pollen extracts blotted to nitrocellulose membranes after SDS-PAGE and inhibition analysis of this binding. RESULTS: A high inhibition of the IgE binding on olive-pollen extract was exhibited by birch, mugwort, pine, and cypress pollens, suggesting that these extracts contain proteins which share common epitopes and thus can be recognized by olive-allergic sera. IgE binding to Gramineae pollen extracts was not inhibited by olive-pollen extract, indicating a primary sensitization of the patients to these species. From the inhibition assays, the presence of an allergen of 45 kDa in the olive pollen, which has no homologous counterparts in other allergenic species, has been inferred. CONCLUSIONS: Olive pollen contains allergens which cross-react with pollens from unrelated species, a fact that could simplify the diagnosis and treatment of pollinosis.

Allergens↗
PubMed2000

Assignment of the disulfide bonds of Ole e 1, a major allergen of olive tree pollen involved in fertilization.

The most prevalent allergen from olive tree pollen, Ole e 1, consists of a single polymorphic polypeptide chain of 145 amino acids which includes six cysteine residues at positions 19, 22, 43, 78, 90 and 131. By using an homogeneous form of the allergen expressed in Pichia pastoris, the array of the disulfide bridges has been elucidated. Specific proteolysis with thermolysin and reverse-phase HPLC separation of the peptides allowed the determination of the disulfide bond between Cys43 and Cys78. Another thermolytic product, which contained three peptides linked by the remaining four cysteines, was digested with Glu-specific staphylococcal V8 protease and the products isolated by reverse-phase HPLC. Amino acid compositions and Edman degradation of the peptide products indicated the presence of the disulfide bonds at Cys19-Cys90 and Cys22-Cys131. These data can help in the analysis of the three-dimensional structure of the protein as well as in studies of its allergenic determinants.

Allergens↗
PubMed2000

Aerosols in a Mediterranean forest: sulfates, particle size distribution, and growth rates.

Particle size distribution measurements in 16 nonlinear intervals covering the 0.1-7.5 microns range and concurrent sulfate concentrations were continuously recorded in September 1996 over the period of two weeks in a Mediterranean forest. Sulfate size distribution was derived from a linear correlation fit between the concentrations and the number of particles recorded at each particle size interval. The results revealed two modal diameters for sulfates, with typical diameters at 0.3 and 0.675 micron. These results were associated with two different dominant chemical mechanisms governing sulfate formation. In order to describe the dominant chemical mechanism, the growth law approach was applied. Growth rates were determined using the parameter estimates of the fitted particle size distribution function. By matching these data with sulfate concentrations, the dominant chemical reactions were identified. The results have shown that sulfate formation is governed by both homogeneous and heterogeneous reactions and that the latter process was dominant. Condensation reactions prevailed in the early morning and late afternoon, and volume reactions at night, particularly in high-moisture conditions. From the observational data, the gas-to-particle conversion rate for sulfur dioxide (SO2) at nighttime was also derived, yielding a 2.18%/hr-1.

Air Pollutants↗
PubMed2000

An evaluation of the LPG vehicles program in the metropolitan area of Mexico City.

The environmental agency in the metropolitan area of Mexico City has launched a program to introduce more energy-efficient modes of transport, one of which is the use of alternative and less polluting fuels. With the perspective in mind, a liquefied petroleum gas (LPG) fleet of vehicles is exempt of the mandatory "one day without a car" program if the emission of pollutants is below the standard authorized for that specific purpose. Today, about 28,000 light-duty vehicles and heavy-duty trucks circulate in the area, most of them as aftermarket converted vehicles. In this work, we evaluated regulated exhaust emission and other parameters on 134 representative vehicles of that fleet. From the data obtained, an estimate of emission factors and their contribution to the global emission in the metropolitan area is provided. It is concluded that more than 95% of the in-use vehicles using LPG presented regulated emissions which exceeded in one or more the environmental regulations values required for certification. The poor maintenance of the vehicles and the type of conversion kit installed could be the culprits of the results obtained.

Air Pollution↗
PubMed2000

Neoadjuvant chemotherapy with ifosfamide, cisplatin, and vinorelbine in advanced squamous cell carcinoma of the cervix.

A phase II trial was performed to assess the efficacy and toxicity of a combination of ifosfamide (IFX), cisplatin (CDDP), and vinorelbine (VNB) as neoadjuvant chemotherapy (NAC) for untreated advanced cervical carcinoma (ACC). Between October 1995 and February 1998, 40 patients were entered in this study. Their median age was 43 years (range: 23-74 years). International Federation of Gynecology and Obstetrics stages were: IIB, 23; IIIB, 13; and IVA, 4. Therapy consisted of: IFX 2,000 mg/m2 1-hour (H) IV infusion days 1 to 3; 2-mercaptoethanesulfonic acid sodium salt (mesna) 400 mg/m2 IV bolus H 0 and 4, and 800 mg/m2 by mouth H 8, days 1 to 3; VNB 25 mg/m2 20-minute IV infusion days 1 and 8; and CDDP 75 mg/m2 IV day 3. Cycles were repeated every 28 days for a total of three courses. Both staging and response (R) assessment were performed by a multidisciplinary team. An objective response (OR) was observed in 24 of 40 patients (60%; 95% confidence interval, 45-75%). Four patients achieved complete response (CR) (10%); 20 partial response (50%); 12 patients stable disease (30%); and 4 progressive disease (10%). Eight of 24 patients (33%) with OR underwent radical surgery, and histologic CRs were recorded in 2 of them. The remaining patients received definitive radiotherapy after NAC. The dose-limiting toxicity was myelosuppression. Leukopenia occurred in 32 patients (80%) and was grade III or IV in 14 patients (36%). Peripheral neuropathy occurred in 9 patients (22%), whereas myalgias occurred in 10 (25%). Constipation was observed in 9 patients (23%); emesis occurred in 35 patients (88%). There were no therapy-related deaths. These results indicate that IFX/CDDP/VNB is an active combination for ACC with moderate toxicity. Implementation of this regimen in a multimodal therapy protocol deserves further study.

Adult↗