Biomedical subjects

C Rodríguez

Publications and source records attributed to C Rodríguez.

At least 73 records · Page 4Linked to original sources

PubMed2001

Determinants of environmental tobacco smoke in a population of Puerto Rican children.

This study was designed to determine among various personal, socioeconomic, and environmental factors those which had the greatest influence on exposure to environmental tobacco smoke (ETS) in a population of children residing in a tropical environment and to compare these results with those obtained in the literature of tobacco exposed children in temperate climates. Urine specimens were collected from 606 healthy Puerto Rican children (2-12 years) living in an industrial area and analyzed for cotinine, a quantitative biomarker for exposure to ETS. Parents completed a questionnaire covering smoking habits and socioeconomic information. Seventy per cent of the children were reported to be exposed to ETS, 50% resulting from exposure to smoke from either or both parents. Major determinants to ETS exposure were found to be presence of smoker, number of smokers, identity of smoker, number of cigarettes smoked in the household and child age with the youngest children suffering twice the exposure of older children. Non-determinants were exposure to smoke other than from the parent, sex of the child, season of the year and several socioeconomic factors including civil and employment status of the mother, mother's age and educational background and whether food stamps were being received. Results of a multiple regression analysis showed that our predictors accounted for 40% of cotinine appearing in the urine. Reasons for this relatively low value may be due in part to precision of our analytic method and lower levels of ambient smoke in our population vs. others that reported higher R(2) values. Predictions from questionnaire information for high ETS exposure were not always the same as those indicated by urinary cotinine emphasizing that the bioindicator, which indicates the actual inhalation of ETS, is a better predictor of exposure than responses from a questionnaire.

Adult↗

PubMed2001

Thyroid-infiltrating B lymphocytes in Graves' disease are related to marginal zone and memory B cell compartments.

B lymphocytes that infiltrate the thyroid (Thy-B cells) in Graves' patients appear to be implicated in the pathophysiology of this disorder. The goal of the present study was to examine the nature of these Thy-B cells. To this end, Thy-B lymphocytes were isolated from surgical thyroidal samples, and their phenotype was determined by using mouse monoclonal antibodies (mAb) directed against a wide variety of surface markers, followed by flow cytometry multicolor analysis. The results show that most Thy-B cells (approximately 60%) exhibited IgM(+) IgD(low to -) surface immunoglobulin (Ig) profile, whereas the minor cell fraction (approximately 30%) consisted of switched IgG(+) memory B lymphocytes. Thy-B cells expressed low levels of CD5, CD23, and CD62L, which distinguished them from the resting B-cell pool, the major B-cell subset in the blood. In addition, they lacked CD38, CD10, and CD71, characteristic molecules for the germinal center B lymphocytes. In addition, Thy-B lymphocytes showed peculiar patterns both of adhesion molecules (CD62L(-), CD44(intermediate)), and of activation molecules (CD69(+), CD80(+), and, in part, CD95(+)). Taken together, these results suggest that the Thy-B lymphocyte subset consists of a combination of IgM(+) B cells resembling marginal zone B lymphocytes, and isotype-switched memory B cells.

Adolescent↗

PubMed2001

One-to-one versus group sessions to improve prescription in primary care: a pragmatic randomized controlled trial.

OBJECTIVES: The objective of the study was to evaluate the effectiveness of 2 educational strategies aimed at improving prescribing standards in primary care. METHODS: A pragmatic controlled trial was designed; the study population included general and family practitioners in Galicia (northwestern Spain) divided into 3 study groups: a one-to-one education group (n = 98), a by-group education group (n = 92), and a control group (n = 405). The educational intervention included explicit recommendations for selecting nonsteroidal anti-inflammatory drugs (NSAIDs) for inflammation signs. Some of the subjects were given reminders. Mixed-effect linear models were applied to data analysis. Analyses were done by intention-to-treat. The dependent variable is a rate with a numerator that is the number of prescribed units of the NSAIDs recommended during intervention; the denominator is the total number of prescribed units of the NSAID total. RESULTS: One-to-one education obtained an average prescribing behavior improvement of 6.5% (P < 0.001) in the 9 months after intervention. In the education group, the average improvement was 2.4% (P < 0.05) for the same period. Statistically significant differences were observed between the group intervention and one-to-one groups. The reminder increased significantly the effectiveness of the one-to-one intervention. CONCLUSIONS: A single, short educational session to primary care doctors can improve their prescribing standards during long periods of > or = 9 months. Of the 2 strategies followed in the trial, one-to-one education has shown to be the most effective. Results also show that the effectiveness of these interventions increases when presented together with written material.

Anti-Inflammatory Agents, Non-Steroidal↗

PubMed2001

African swine fever virus IAP homologue inhibits caspase activation and promotes cell survival in mammalian cells.

African swine fever virus (ASFV) A224L is a member of the inhibitor of apoptosis protein (IAP) family. We have investigated the antiapoptotic function of the viral IAP both in stably transfected cells and in ASFV-infected cells. A224L was able to substantially inhibit caspase activity and cell death induced by treatment with tumor necrosis factor alpha and cycloheximide or staurosporine when overexpressed in Vero cells by gene transfection. We have also observed that ASFV infection induces caspase activation and apoptosis in Vero cells. Furthermore, using a deletion mutant of ASFV lacking the A224L gene, we have shown that the viral IAP modulates the proteolytic processing of the effector cell death protease caspase-3 and the apoptosis which are induced in the infected cells. Our findings indicate that A224L interacts with the proteolytic fragment of caspase-3 and inhibits the activity of this protease during ASFV infection. These observations could indicate a conserved mechanism of action for ASFV IAP and other IAP family members to suppress apoptosis.

African Swine Fever Virus↗

PubMed2001

3-hydroxy-3-methylglutaryl coenzyme a reductase inhibition prevents endothelial NO synthase downregulation by atherogenic levels of native LDLs: balance between transcriptional and posttranscriptional regulation.

Atherogenic levels of native low density lipoproteins (nLDLs) decrease the bioavailability of endothelium-derived NO and downregulate endothelial NO synthase (eNOS) expression in cultured human endothelial cells. Here, we show that simvastatin, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor, within the therapeutic range (0.01 to 1 micromol/L) prevented the downregulation of eNOS mRNA and protein promoted by nLDL (180 mg cholesterol/dL, 48 hours) in human umbilical vein endothelial cells. This effect of simvastatin was completely reversed by mevalonate, the product of the reaction, and to a lesser extent by farnesol and geranyl geraniol. Simvastatin significantly stabilized eNOS mRNA in cells treated with nLDL during 48 hours (eNOS mRNA half-life approximately 11 hours in controls versus >24 hours in nLDL per 0.1 micromol/L simvastatin-treated cells). The downregulation of eNOS by nLDL was abrogated by cycloheximide, an inhibitor of protein synthesis, and by N-acetyl-leucyl-leucyl-norleucinal, a protease inhibitor that reduces the catabolism of sterol regulatory element binding proteins. Sterol deprivation increased the downregulation produced by nLDL on eNOS and sterol regulatory element binding protein-2 expression levels. However, no differential modulation of the retardation bands corresponding to the putative sterol-responsive element present in the eNOS promoter was detected by electrophoretic mobility shift assay. Our results suggest that nLDL promote eNOS downregulation operating at a transcriptional level, whereas simvastatin prevents such an effect through a posttranscriptional mechanism.

Arteriosclerosis↗

PubMed2001

Birth weight influences blood pressure values and variability in children and adolescents.

The objective of the present study was to assess the relationships between birth weight and the values and variability of ambulatory blood pressure. Six hundred thirty healthy children (369 girls) age 4 to 18 years (mean, 9.9 years) born at term after a normotensive pregnancy were included. The subjects were divided into 5 groups according to birth weight. For each subject, a 24-hour ambulatory blood pressure monitoring was performed according to the protocol designed. Average and variability (estimated as the standard deviation) of ambulatory blood pressure and heart rate were calculated separately for 24-hour, daytime, and nighttime periods. When values were adjusted for gender, current age, weight, and height, children with the lowest birth weights had the highest ambulatory blood pressure values and variability, whereas no differences in heart rate were observed. Multiple regression analysis showed that although current weight was the strongest predictor for 24-hour systolic blood pressure (P<0.001), there was also an independent and significant inverse relationship for birth weight (P<0.002) after controlling for gender, current age, and height. Likewise, birth weight was independently and inversely correlated with 24-hour systolic blood pressure variability (P<0.03). In conclusion, children who had lower birth weights tended to have not only the highest blood pressure values but also the highest blood pressure variability, independent of the increases in ambulatory blood pressure values. Knowing that high blood pressure variability is at least partially independent of blood pressure values, the importance of this variability on further blood pressure rises and/or on vascular damage later in life needs to be assessed in future studies.

Adolescent↗

PubMed2001

[Upper digestive haemorrhage due to Mallory-Weiss syndrome. Role of endoscopic sclerotherapy].

BACKGROUND: Although Mallory-Weiss syndrome is responsible for between 0.5 and 17% of the cases of upper digestive haemorrhage, the information existing on the endoscopic treatment of this syndrome is scarce. MATERIAL AND METHODS: We made a retrospective study of 71 patients with haemorrhage due to Mallory-Weiss syndrome, dividing them into two groups according to the treatment they had received (medical or medical-endoscopic). Hence, 60 patients (30 with clean laceration, 9 with signs of prior haemostasia and 21 with fresh clotting) had been treated with procinetics and/or antisecretories alone, while the 11 remaining (8 with active haemorrhage, 2 with visible vessel and 1 with fresh clotting) had also received endoscopic treatment with sclerotherapy. We compared the clinical and analytical characteristics and the evolution of both groups of patients, analysing the data by means of the Mann-Whitney U and the chi 2 test. RESULTS: The endoscopic sclerosis group showed maelenas more frequently and more severe analytical data of haemorrhage (p<0.01). Endoscopic sclerosis brought initial control of the haemorrhage in all the patients, with a low index of haemorrhage relapse, similar to the group receiving exclusively medical treatment. CONCLUSIONS: In our series, the patients with Mallory-Weiss syndrome with active bleeding or visible vessel presented a haemorrhage with a greater clinical and analytical repercussion. In this group of patients, endoscopic sclerotherapy controlled the haemorrhage and/or prevented rebleeding, in the absence of complications.

English Abstract↗

PubMed2001

Hematological, protein electrophoresis and cholinesterase values of free-living nestling peregrine falcons in Spain.

Protein electrophoresis, hematological and cholinesterase values were determined in 32 nestling free-living peregrine falcons (Falco peregrinus) (15- to 27-days-old) in order to establish normal reference values for this population. The following values (mean +/- SD) were observed: prealbumin 0.31 +/- 0.04 g/dl, albumin 1.25 +/- 0.06 g/dl, alpha1 and alpha2-globulin 0.23 +/- 0.02 and 0.16 +/- 0.02 g/dl respectively, beta-globulin 1.02 +/- 0.05 g/dl, gamma-globulin 0.060 +/- 0.08 g/dl, total protein 3.79 +/- 0.18 g/dl, 21.26 +/- 1.30 white blood cells/microl (1 x 10(3)), 2.17 +/- 0.07 red blood cells/microl (1 x 10(6)), packed cell volume 37.58 +/- 0.82%, hemoglobin 20.96 +/- 0.29 g/dl, heterophils 61.14 +/- 2.50% and cholinesterase 1,184 +/- 75 IU/L. There were no difference in any of these parameters among males and females. The hematological values obtained could be considered as representative values in free-living nestling peregrine falcons.

Albumins↗

PubMed2001

Primary HIV-1 drug resistance in Spain before and after the introduction of protease inhibitors.

The prevalence of genotypic resistance to nucleoside analogues was examined in 150 naive individuals with chronic HIV-1 infection acquired before June 1996, when protease inhibitors began to be used in Spain, and in a group of 52 recent seroconverters infected since 1997. Overall, the prevalence of subjects carrying nucleoside-resistant genotypes was similar in both groups (12.6% and 15.4%, respectively). A polymorphism at codon 70 accounted for more than half of cases (63.1%) in naive individuals infected before protease inhibitors became available, in contrast most recent seroconverters carried genotypes with one or more key nucleoside resistance mutations, mainly associated with lack of sensitivity to zidovudine or lamivudine (prevalence 9.6% and 5.9%, respectively). When only key mutations were considered in each of the two periods, the prevalence of nucleoside-resistant genotypes was increased significantly among recent seroconverters (13.5% vs. 4.7%; P<0.05). The relatively high rate of resistance to nucleosides in Spain justifies the introduction of drug resistance testing in naive recent seroconverters before beginning antiretroviral therapy.

Anti-HIV Agents↗

PubMed2001

Nutrition and cataract in low-income Mexicans: experience in an Eye camp.

Surgical Eye-camps for cataract treatment of low-income adult Mexicans have been undertaken over the last 10 years. Despite the high prevalence of cataracts among these subjects, no assessment of their nutritional or health status has ever been made. We compare the results obtained for 81 adults (44 men and 37 women) who received treatment in May 1997 with those for a "control" group of age and sex-matched but affluent individuals in Mexico City. alpha-Tocopherol and beta-carotene were assessed and analysed by HPLC and colorimetric procedures, respectively. The plasma tocopherol to cholesterol ratio did not reveal deficiencies of this vitamin, and only 5 patients (2 men and 3 women) had low beta-carotene plasma levels. The patients had high BMI values, with 32% of men and 30% of women overweight, and 2% and 14%, respectively, obese, with higher glucose, cholesterol and triglyceride values reflecting enhanced insulin resistance and lipid abnormalities. The alkaline phosphatase values were elevated suggesting that many of these blind patients are osteomalacic because they now remain indoors. Although it has been suggested that an adequate intake of carotenes and tocopherol are associated with absence of cataract, this appears not to be the case in our study population. Surveys in Mexico have revealed, however, a highly prevalent deficiency of other vitamins such as niacin and riboflavin, both of which have been proved to be protective against cataract. It appears that nutritional deficiencies, obesity, incipient diabetes and lipid disorders co-exist in modern Mexico. We have identified a need for research to aid the design of preventive nutritional approaches at the population level that could be applied in parallel with ongoing surgical treatment.

Adult↗

PubMed2001

Walnut-enriched diet increases the association of LDL from hypercholesterolemic men with human HepG2 cells.

In a randomized, cross-over feeding trial involving 10 men with polygenic hypercholesterolemia, a control, Mediterranean-type cholesterol-lowering diet, and a diet of similar composition in which walnuts replaced approximately 35% of energy from unsaturated fat, were given for 6 weeks each. Compared with the control diet, the walnut diet reduced serum total and LDL cholesterol by 4.2% (P = 0.176), and 6.0% (P = 0.087), respectively. No changes were observed in HDL cholesterol, triglycerides, and apolipoprotein A-I levels or in the relative proportion of protein, triglycerides, phospholipids, and cholesteryl esters in LDL particles. The apolipoprotein B level declined in parallel with LDL cholesterol (6.0% reduction). Whole LDL, particularly the triglyceride fraction, was enriched in polyunsaturated fatty acids from walnuts (linoleic and alpha-linolenic acids). In comparison with LDL obtained during the control diet, LDL obtained during the walnut diet showed a 50% increase in association rates to the LDL receptor in human hepatoma HepG2 cells. LDL uptake by HepG2 cells was correlated with alpha-linolenic acid content of the triglyceride plus cholesteryl ester fractions of LDL particles (r(2) = 0.42, P < 0.05). Changes in the quantity and quality of LDL lipid fatty acids after a walnut-enriched diet facilitate receptor-mediated LDL clearance and may contribute to the cholesterol-lowering effect of walnut consumption.

Adult↗

PubMed2000

Base-promoted isomerization of cis-4-formyl-2-azetidinones: chemoselective C4-epimerization vs rearrangement to cyclic enaminones.

Two simple, efficient, and complementary methods for the regiospecific C4-epimerization of cis-4-formyl-2-azetidinones 1-3 are described. The first method uses 40% aqueous dimethylamine as reagent in heterogeneous medium with benzene at room temperature, in the presence of benzyltributylammonium bromide (3-4 mol%) as the phase-transfer catalyst. This transformation tolerates alkyl, alkenyl, alkynyl, aryl, and alkoxy substituents at the C3 of the 2-azetidinone ring. However, limitations of this isomerization are as follows: (i) only N-(p-methoxyphenyl)-beta-lactams can be used, and (ii) transformation is less compatible with heteroatomic substituents bonded to the C3 position of the 2-azetidinone ring. A highly general solution to these problems relies on the use of sodium carbonate as the isomerization reagent in different solvents. We also describe a novel base-promoted rearrangement of the beta-lactam ring to cyclic enaminones 6 and 21, involving an E1cB-elimination reaction in cis-4-formyl-2-azetidinones.

Anti-Bacterial Agents↗

PubMed2000

Mutations in GAL2 or GAL4 alleviate catabolite repression produced by galactose in Saccharomyces cerevisiae.

Galactose does not allow growth of pyruvate carboxylase mutants in media with ammonium as a nitrogen source, and inhibits growth of strains defective in phosphoglyceromutase in ethanol-glycerol mixtures. Starting with pyc1, pyc2, and gpm1 strains, we isolated mutants that eliminated those galactose effects. The mutations were recessive and were named dgr1-1 and dgr2-1. Strains bearing those mutations in an otherwise wild-type background grew slower than the wild type in rich galactose media, and their growth was dependent on respiration. Galactose repression of several enzymes was relieved in the mutants. Biochemical and genetic evidence showed that dgr1-1 was allelic with GAL2 and dgr2-1 with GAL4. The results indicate that the rate of galactose consumption is critical to cause catabolite repression.

Journal Article↗

PubMed2000

Cubic-Phase-Based Concentrated Emulsions.

The effect of different types of added oil on the formation of a discontinuous micellar-type cubic phase was investigated in water-polyoxyethylene dodecyl ether (C(12)EO(25)) systems by phase study and small-angle X-ray scattering. The thermal stability of the cubic phase increases upon addition of oil, especially short-chain hydrocarbons. However, in the heptane system, the maximum melting temperature of the cubic phase is lower than that for decane due to the formation of a different liquid crystal phase. The effect of polyols on C(12)EO(25) cubic phases was also investigated. It was found that the thermal stability of the cubic phase decreases with polyol concentration. The destabilizing effect becomes large as the polyol molecule penetrates further into the surfactant palisade layer. Although the solubilization of oil in the cubic phase is very low, a large amount of excess oil can be incorporated and a transparent cubic-phase-based concentrated emulsion is formed. The transparency is attributed to the very small difference in the refractive indices between the cubic and excess-oil phases. Copyright 2000 Academic Press.

Journal Article↗

PubMed2000

Comparison of various reversed-phase columns for the simultaneous determination of ephedrines in urine by high-performance liquid chromatography.

Different reversed-phase columns for basic analytes were compared for the simultaneous determination of ephedrines in urine, such as LiChrospher 60 RP-Select B, LiChrospher 100 RP18, Hypersil BDS-C18, Inertsil ODS-2, Spherisorb ODS-B and Symmetry Shield RP8. Symmetry Shield was the only column which did not require the use of high concentrations of buffer and triethylamine. With this column, a good separation of the six ephedrines and the internal standard was achieved using 50 mM phosphate buffer-25 mM triethylamine as a mobile phase. Linearity, precision and accuracy were satisfactory for the levels usually found in urine. Due to these all parameters the developed analytical method was found to be suitable for the application in the doping field.

Chromatography, High Pressure Liquid↗

PubMed2000

Genetic analysis of HIV-1 samples from Spain.

To characterize the viruses responsible for the HIV-1 epidemic in Spain, we genetically characterized 79 samples obtained from Spanish patients with different risk practices (injecting drug users and male homosexuals) in two regions (Madrid and Navarra). Genetic characterization was carried out by nucleotide sequencing in the C2-V3-C3 region and by phylogenetic analysis. All samples were of subtype B except one that clustered with clade F. Because no segregation of samples was determined according to the risk group of patients nor to their geographic origin, the Spanish samples analyzed constitute a single group of viruses. These data, along with the starlike topology of the phylogenetic tree, support the existence of a single introduction of HIV-1 subtype B in Spain. The mean genetic distance among subtype B sequences was of 13.9%+/-0.06% (range, 5%-25%), suggesting an epidemic of long evolution. Analysis of sequences in relation to isolation dates revealed an increase in the heterogeneity of the nucleotide sequences with time. According to these data, a divergence rate of 0.49%+/-0.11% per year was calculated for the Spanish samples during the period analyzed.

Amino Acid Sequence↗

PubMed2000

Genetic variation in the renin-angiotensin system and athletic performance.

The D allele at the angiotensin-I-converting enzyme (ACE)-insertion/deletion polymorphism has been associated with an increased risk of developing several pathological processes, such as coronary heart disease and ventricular hypertrophy. Individuals with the DD genotype show a significantly increased left-ventricular mass in response to physical training, compared to the II genotype (which would be associated with the lowest plasma ACE levels) and the ID genotype. The II genotype has been linked to a greater anabolic response. In accordance with a role for ACE in the response to rigorous physical training, a higher frequency of the I allele has been reported to exist among elite rowers and high-altitude mountaineers. Sixty elite (professional) athletes (25 cyclists, 20 long-distance runners, and 15 handball players), and 400 healthy controls were genotyped for the DNA polymorphisms of the ACE, angiotensinogen (Ang) and angiotensin receptor type 1 (AT1) genes. Plasma ACE levels showed a strong correlation with the I/D genotype in our population. The I-allele occurred at a significantly higher frequency in athletes compared to controls (P = 0.0009). Gene and genotype frequencies for the Ang and AT1 polymorphisms did not differ between athletes and controls. Since the frequency of the ACE I allele was significantly increased among our elite athletes, we conclude that the ACE polymorphism represents a genetic factor that contributes to the development of an elite athlete.

Adult↗

PubMed2000

Exact analytical solution of the convolution integral equation for a general profile fitting function and Gaussian detector kernel.

One of the most important aspects in the metrology of radiation fields is the problem of the measurement of dose profiles in regions where the dose gradient is large. In such zones, the 'detector size effect' may produce experimental measurements that do not correspond to reality. Mathematically it can be proved, under some general assumptions of spatial linearity, that the disturbance induced in the measurement by the effect of the finite size of the detector is equal to the convolution of the real profile with a representative kernel of the detector. In this work the exact relation between the measured profile and the real profile is shown, through the analytical resolution of the integral equation for a general type of profile fitting function using Gaussian convolution kernels.

Densitometry↗