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P Carrasco

Publications and source records attributed to P Carrasco.

At least 19 recordsLinked to original sources
PubMed2006

A real-time RT-PCR assay for quantifying the fitness of tobacco etch virus in competition experiments.

Relative fitness determination has become a standard tool in experimental virus evolution studies. In this type of studies, the tested strain is mixed with a reference strain, which differs in an easy-to-score and genetically stable marker, and allowed to compete for a limited common pool of resources during a given number of generations. In this report, a TaqMan real-time PCR methodology is proposed for quantifying the relative fitness of tobacco etch potyvirus strains (TEV) in in planta mixed infections with a reference TEV strain. Two different forward primers along with a common reverse one are used into separated reactions mixes from the same RNA preparation. The reference strain, named TEV-PC1, was genetically engineered to carry a neutral marker in a highly conserved region of the RNA polymerase NIb gene. This marker allows tracking the frequency of both competitors during competition experiments by real-time quantitative PCR using specific primers. Both the reproducibility and sensitivity of the method have been explored. Reproducibility was assessed by running multiple competition experiments for the same genotype. Sensitivity was assessed by comparing the results of competition experiments against TEV-PC1 of 24 single-nucleotide substitutions mutants.

Gene Amplification↗
PubMed2006

Dose evaluation in lung-equivalent media in high-energy photon external radiotherapy.

In high-energy photon external radiotherapy treatment planning systems (TPSs) are used to calculate the dose to the target volume and the dose distribution around it. Commonly used TPSs include algorithms based on measurements in water and often fail in the estimate of dose in the presence of heterogeneities. In this study TL detectors were used to study the reliability of the Cadplan (Varian) TPS in the presence of low-density heterogeneities such as the lung for 6 and 18 MV photon beams at different field sizes. TL measurements were compared with TPS calculations and Monte Carlo simulations performed with the PENELOPE MC code. In a phantom with lung heterogeneity, TL measurements and MC simulations agreed, with an average deviation inside the lung of 2%. In contrast, TPS results overestimated the dose inside the lung, with a maximum deviation of 39% for the 18 MV photon beam and a field size of 2 x 2 cm(2).

Algorithms↗
PubMed2005

Analysis of the expression of some stress induced genes in several commercial wine yeast strains at the beginning of vinification.

AIMS: During fermentation yeast cells should cope with stress conditions. We pursue a better understanding of the stress response in wine yeasts at the beginning of vinification. METHODS AND RESULTS: We analyse by means of quantitative PCR the expression of several stress induced genes in 24 efficient commercial wine yeast strains at the beginning of vinifications performed under standard conditions or with small variations in pH and temperature. In all cases, high levels (with differences among strains) of GPD1 mRNA but quite low expression of other stress genes (TRX2, HSP104 and SSA3) were found. For all these genes, mRNA levels increase as temperature decreases or pH increases. CONCLUSIONS: Important levels of expression of GPD1 (but not of other stress genes) are required during the first hours of vinification, because of the need for glycerol production to counteract the hyperosmotic stress at this point. The differences among strains suggest that certain level of expression is enough to ensure the continuity of the process. Variations in the pH and temperature of the vinification can affect gene expression. SIGNIFICANCE AND IMPACT OF THE STUDY: A common pattern of stress response between efficient wine strains exists, which could be used as a criterion for selection. Studies of this kind can allow the establishment of connections between gene expression and physiological traits.

Fermentation↗
PubMed2005

Pantak Therapax SXT 150: performance assessment and dose determination using IAEA TRS-398 protocol.

The performance assessment and beam characteristics of the Therapax SXT 150 unit, which encompass both low and medium-energy beams, were evaluated. Dose determination was carried out by implementing the International Atomic Energy Agency (IAEA) TRS-398 protocol and measuring all the dosimetric parameters in order to have a solid, consistent and reliable data set for the unit. Mechanical movements, interlocks and applicator characteristics agreed with specifications. The timer exhibited good accuracy and linearity. The output was very stable, with good repeatability, long-term reproducibility and no dependence on tube head orientation. The measured dosimetric parameters included beam first and second half-value layers (HVLs), absorbed dose rate to water under reference conditions, central axis depth dose distributions, output factors and beam profiles. Measured first HVLs agreed with comparable published data, but the homogeneity coefficients were low in comparison with typical values found in the literature. The timer error was significant for all filters and should be taken into consideration for the absorbed dose rate determination under reference conditions as well as for the calculation of treatment times. Percentage depth-dose (PDD) measurements are strongly recommended for each filter-applicator combination. The output factor definition of the IAEA TRS-398 protocol for medium-energy X-ray qualities involves the use of data that is difficult to measure. Beam profiles had small penumbras and good symmetry and flatness except for the lowest energy beam, for which a heel effect was observed.

Calibration↗
PubMed2004

Burden of hospitalizations attributable to rotavirus infection in children in Spain, period 1999-2000.

The aim of this study is to provide estimates on the incidence of rotavirus infection requiring hospitalization in children <or=5 years of age during the 1999-2000 period in Spain and the associated direct cost of these hospitalizations. Hospital admissions attributable to rotavirus were estimated by using data on confirmed laboratory reports of rotavirus and hospital admissions due to acute gastroenteritis. During the study period a total of 32541 cases of pathogens responsible for acute gastroenteritis were reported to the microbiological information national system (SIM) and 14.0% were rotavirus. The proportion of laboratory-confirmed rotavirus cases was extrapolated to the total number of hospitalizations for acute gastroenteritis in children <or=5 years of age. An annual incidence of 1.0 hospital admissions attributable to rotavirus per 1000 persons <or=5 years of age was found, although during the winter season it reached 2.5 hospitalizations per 1000. Overall, the estimated annual number of days of hospitalization attributable to rotavirus was 8742 days that results in a cost of 3.6 million per year.

Acute Disease↗
PubMed2004

Correlation between thrombus regression and recurrent venous thromboembolism. Examining venographic and clinical effects of low-molecular-weight heparins: a meta-analysis.

We analyzed the correlation between thrombus regression on control venography performed after discontinuation of heparin therapy and recurrent venous thromboembolism (VTE) detected during clinical follow-up in randomized trials comparing low-molecular-weight heparin (LMWH) and unfractionated heparin (UFH) in patients with deep vein thrombosis (DVT). Data were abstracted from MEDLINE, conference abstracts and reference lists of previous reviews. Randomized, controlled trials comparing LMWH and UFH for the treatment of DVT using a combined venographic and clinical assessment and with at least 2 months of follow-up were selected. The proportions of patients with thrombus regression on control venography performed soon after discontinuation of heparin therapy and recurrent VTE at 2-6 months were independently collected by two researchers. Thirteen studies met the inclusion criteria. There was a strong inverse correlation between thrombus regression and recurrent VTE (r =- 0.70; P =0.008). The venographic effect varied between the different LMWHs (P = 0.013). A very strong correlation was found when the results were pooled by the type of LMWH used (r = - 0.84; P=0.037). No influence of the dose interval used on the venographic effect (P=0.156) or on recurrent VTE (P=0.218) was shown. The lack of thrombus regression in venography, performed soon after heparin discontinuation, was correlated with clinical recurrence. Non-invasive imaging techniques should be relevant to identify non-responders and to assess the optimal duration of initial heparin treatment in daily clinical practice.

Heparin, Low-Molecular-Weight↗
PubMed2004

Comparison study of MOSFET detectors and diodes for entrance in vivo dosimetry in 18 MV x-ray beams.

The feasibility of dual bias dual metal oxide semiconductor field effect transistors (MOSFETs) for entrance in vivo dose measurements in high energy x-rays beams (18 MV) was investigated. A comparison with commercially available diodes for in vivo dosimetry for the same energy range was performed. As MOSFETs are sold without an integrated build-up cap, different caps were tested: 3 cm bolus, 2 cm bolus, 2 cm hemispherical cap of a water equivalent material (Plastic Water) and a metallic hemispherical cap. This metallic build-up cap is the same as the one that is mounted on the in vivo diode used in this study. Intrinsic precision and response linearity with dose were determined for MOSFETs and diodes. They were then calibrated for entrance in vivo dosimetry in an 18 MV x-ray beam. Calibration included determination of the calibration factor in standard reference conditions and of the correction factors (CF) when irradiation conditions differed from those of reference. Correction factors for field size, source surface distance, wedge, and temperature were determined. Sensitivity variation with accumulated dose and the lifetime of both types of detectors were also studied. Finally, the uncertainties of entrance in vivo measurements using MOSFET and diodes were discussed. Intrinsic precision for MOSFETs for the high sensitivity mode was 0.7% (1 s.d.) as compared to the 0.05% (1 s.d.) for the studied diodes. The linearity of the response with dose was excellent (R2 = 1.000) for both in vivo dosimetry systems. The absolute values of the studied correction factors for the MOSFETs when covered by the different build-up caps were of the same order of those determined for the diodes. However, the uncertainties of the correction factors for MOSFETs were significantly higher than for diodes. Although the intrinsic precision and the uncertainty on the CF was higher for MOSFET detectors than for the studied diodes, the total uncertainty in entrance dose determination, once they were calibrated, was of 2.9% (1 s.d.) while for diodes it was 2.0% (1 s.d.). MOSFETs showed no sensitivity variation with accumulated dose or temperature. When used in the high sensitivity mode, after approximately 50 Gy of accumulated dose MOSFETs could no longer be used as radiation dosimeters. In conclusion, MOSFETs can be used for entrance in vivo dosimetry in high energy x-rays beams if covered by an appropriate build-up cap. Metallic build-up caps, such as those used for in vivo diodes, have the advantage of greater patient comfort and less perturbation of the treatment field than the other build-up caps tested, while keeping the correction factors of the same order.

Body Burden↗
PubMed2004

Comparison of dose calculation algorithms in phantoms with lung equivalent heterogeneities under conditions of lateral electronic disequilibrium.

An extensive set of benchmark measurement of PDDs and beam profiles was performed in a heterogeneous layer phantom, including a lung equivalent heterogeneity, by means of several detectors and compared against the predicted dose values by different calculation algorithms in two treatment planning systems. PDDs were measured with TLDs, plane parallel and cylindrical ionization chambers and beam profiles with films. Additionally, Monte Carlo simulations by means of the PENELOPE code were performed. Four different field sizes (10 x 10, 5 x 5, 2 x 2, and 1 x 1 cm2) and two lung equivalent materials (CIRS, p(w)e=0.195 and St. Bartholomew Hospital, London, p(w)e=0.244-0.322) were studied. The performance of four correction-based algorithms and one based on convolution-superposition was analyzed. The correction-based algorithms were the Batho, the Modified Batho, and the Equivalent TAR implemented in the Cadplan (Varian) treatment planning system and the TMS Pencil Beam from the Helax-TMS (Nucletron) treatment planning system. The convolution-superposition algorithm was the Collapsed Cone implemented in the Helax-TMS. The only studied calculation methods that correlated successfully with the measured values with a 2% average inside all media were the Collapsed Cone and the Monte Carlo simulation. The biggest difference between the predicted and the delivered dose in the beam axis was found for the EqTAR algorithm inside the CIRS lung equivalent material in a 2 x 2 cm2 18 MV x-ray beam. In these conditions, average and maximum difference against the TLD measurements were 32% and 39%, respectively. In the water equivalent part of the phantom every algorithm correctly predicted the dose (within 2%) everywhere except very close to the interfaces where differences up to 24% were found for 2 x 2 cm2 18 MV photon beams. Consistent values were found between the reference detector (ionization chamber in water and TLD in lung) and Monte Carlo simulations, yielding minimal differences (0.4%+/-1.2%). The penumbra broadening effect in low density media was not predicted by any of the correction-based algorithms, and the only one that matched the experimental values and the Monte Carlo simulations within the estimated uncertainties was the Collapsed Cone Algorithm.

Algorithms↗
PubMed2003

Safety and effectiveness of replacing standard doxazosin with doxazosin in the gastrointestinal therapeutic system (GITS) formulation in elderly hypertensive patients.

The objective of this paper is to evaluate the safety and effectiveness of using doxazosin standard formulation in elderly hypertensive patients who were either uncontrolled or newly diagnosed, and replacing standard doxazosin with doxazosin in the gastrointestinal therapeutic system (GITS) formulation. We designed a postmarketing surveillance, open-label non-comparative, multicentre, clinical study covering primary care patients aged 65 years or older diagnosed with essential uncontrolled arterial hypertension. The study covered a period of 6-9 months, divided into two phases. Phase I involved a minimum of three and maximum of six months in treatment with standard doxazosin; phase II began with the changeover from standard doxazosin to the GITS formulation and lasted 12 weeks. Of the 1705 patients initially enrolled, 1292 (75.8%) completed the study. Reduction in systolic blood pressure was 22.3 mmHg (13.7%) in phase I, and 3.9 mmHg (2.77%) in phase II; reduction in diastolic blood pressure was 12.4 mmHg (13.2%) in phase I, and 2.4 mmHg (2.9%) in phase II. The percentage of controlled patients was 40.5% (691/1705) by the end of phase I and 45.3% (776/1705) by the end of phase II. A total of 154 patients suffered adverse events (AE), 127 during phase I and 27 in phase II. We conclude that doxazosin in its two formulations is effective and safe for the purpose of lowering blood pressure in elderly patients.

Aged↗
PubMed2002

Epidemiology of pneumonia hospitalizations in Spain, 1995-1998.

OBJECTIVES: This epidemiological survey was undertaken to estimate the burden of hospital admissions for pneumonia in Spain during a four-year period (1995-1998). METHODS: Data were obtained from the national surveillance system for hospital data. RESULTS: There were 231,512 hospital admissions for pneumonia (ICD 9 CM 480-486; first listed diagnosis) during this period, that is an annual incidence of 177 cases per 100,000 population. The incidence was higher in children <5 years of age and in persons >or=65 years compared with other age groups. The annual cost of these hospitalizations to the National Health Care System was of 127 million ECUS. CONCLUSIONS: Preventive measures, such as vaccination of population groups at high risk, to reduce pneumonia-related morbidity could result in large cost savings to the National Health Care System.

Adolescent↗
PubMed2001

Epidemiology of primary varicella hospitalizations in Spain.

An approach to the burden of varicella can be obtained from information on the hospitalizations. Data were obtained from the national surveillance system for hospital data. All hospital discharges for varicella were analyzed for the 1995-1998 period. A total of 3632 primary varicella-related discharges were identified, representing an annual incidence of 2.8 per 100,000 population. A total of 58% of cases were <10 years of age and 33% were 21-50 years old. Each year primary varicella will be responsible for 6174 days of hospitalization, representing an annual cost of 1.6 million euros. There is substantial severe morbidity each year from varicella that, to reduce, would require vaccination of infants and susceptible adults.

Adolescent↗
PubMed2001

Hospital admissions for pertussis in Spain, 1995-1998.

This epidemiological survey was undertaken to estimate the annual burden of hospitalizations for pertussis in Spain during a four-year period 1995-1998. Data were obtained from the national surveillance system for hospital data. All hospital discharges for pertussis (ICD-9- CM 033) were analyzed. The annual incidence of hospitalization for pertussis was 1.7 per 100,000 population. Eighty-nine percent of the cases were < 1 year of age (incidence of 78 per 100,000) and 95% were < or =5 years of age (incidence of 28 per 100,000). During the study period, 14 deaths were reported among patients hospitalized by pertussis. Despite of the high immunization rates, many pertussis cases occur each year, mostly of them among very young children.

Adolescent↗
PubMed2001

[Factors related to psychotropic drugs consumption among the Spanish adult population. Data from the Spanish National Health Surveys for 1993, 1995 and 1997].

BACKGROUND: In this study, the aim is the identification of the factor associated with psychotropic drug use among the Spanish adult population. MATERIALS AND METHOD: A descriptive and cross-sectional survey is carried out using data from the Spanish National Health Surveys from 1993, 1995 and 1997. As subjects of the study we have chosen the spanish adult population (aged 16 plus). INDEPENDENT VARIABLES: socio-demographic factors and health profile. Dependent variables are the overall consumption of psychotropic drug, both prescribed and no prescribed. RESULTS: Prevalence of psychotropic drug consumption is higher among women (6.9% in 1993; 9.9% in 1995, and 9.7% in 1997) than among men (3.1% in 1993; 4.8% in 1995, and 4.7% in 1997). According to multivariance analysis, alcohol consumption have negative association, anxiety or sleep disorder and depression seem to be strongly associated (OR = 22.44; CI 95%, 13.06-38.56 women, and OR = 42.97; CI 95%, 17.69-104.40 men). CONCLUSIONS: Prevalence of psychotropic drug consumption is higher in women than in men. The most strongly associated variable is nervous or sleep disorder and depression.

Adolescent↗
PubMed2001

Analysis of the stress resistance of commercial wine yeast strains.

Alcoholic fermentation is an essential step in wine production that is usually conducted by yeasts belonging to the species Saccharomyces cerevisiae. The ability to carry out vinification is largely influenced by the response of yeast cells to the stress conditions that affect them during this process. In this work, we present a systematic analysis of the resistance of 14 commercial S. cerevisiae wine yeast strains to heat shock, ethanol, oxidative, osmotic and glucose starvation stresses. Significant differences were found between these yeast strains under certain severe conditions, Vitilevure Pris Mouse and Lalvin T73 being the most resistant strains, while Fermiblanc arom SM102 and UCLM S235 were the most sensitive ones. Induction of the expression of the HSP12 and HSP104 genes was analyzed. These genes are reported to be involved in the tolerance to several stress conditions in laboratory yeast strains. Our results indicate that each commercial strain shows a unique pattern of gene expression, and no clear correlation between the induction levels of either gene and stress resistance under the conditions tested was found. However, the increase in mRNA levels in both genes under heat shock indicates that the molecular mechanisms involved in the regulation of their expression by stress function in all of the strains.

Ethanol↗
PubMed2000

Review of regional measles surveillance data in the Americas, 1996-99.

BACKGROUND: In 1994, ministers of health of countries of North and South America established the goal of measles eradication from the western hemisphere by 2000. To accomplish this goal, the Pan American Health Organization (PAHO) developed an enhanced measles vaccination strategy. METHODS: PAHO's measles eradication vaccination strategy has evolved into three principal components; a catch-up measles vaccination campaign, maintenance of high vaccination coverage (keep-up), and periodic follow-up measles vaccination campaigns. To monitor progress towards measles eradication, measles surveillance has been strengthened, including the laboratory investigation of suspected measles cases. FINDINGS: Both the catch-up and follow-up mass campaigns achieved high vaccination coverages in the respective targeted age groups. In 1996, only 2109 confirmed measles cases were reported in the Americas. In 1997, there was a resurgence of measles in the Americas, mostly as a result of a large measles outbreak with over 42000 cases, which occurred mainly among unvaccinated young adults in Sao Paulo State, Brazil. By 1998, there was a reduction in the number of reported confirmed measles cases, with a total of 14474 cases. Reduction of cases continued to the end of 1999, with a total of only 2828 confirmed cases. INTERPRETATION: PAHO's measles eradication strategy has been effective in interrupting transmission and maintaining the absence of measles virus circulation in most parts of the Americas. The PAHO experience provides strong evidence that with full implementation of an appropriate vaccination strategy, measles transmission can be effectively interrupted.

Adolescent↗
PubMed1998

Differential expression of the S-adenosyl-L-methionine synthase genes during pea development.

Two genes coding for S-adenosyl-l-methionine synthase (SAMS, EC 2.5. 1.6) were previously isolated from pea (Pisum sativum) ovaries. Both SAMS genes were highly homologous throughout their coding regions but showed a certain degree of sequence divergence within the 5' and the 3' untranslated regions. These regions have been used as gene-specific probes to analyze the differential expression of SAMS1 and SAMS2 genes in pea plants. The ribonuclease protection assay revealed different expression patterns for each individual gene. SAMS1 was strongly expressed in nearly all tissues, especially in roots. SAMS2 expression was weaker, reaching its highest level at the apex. Following pollination, SAMS1 was specifically up-regulated, whereas SAMS2 was expressed constitutively. The up-regulation of SAMS1 during ovary development was also observed in unpollinated ovaries treated with auxins. In unpollinated ovaries an increase in SAMS1 expression was observed as a consequence of ethylene production associated with the emasculation process. In senescing ovaries both SAMS1 and SAMS2 genes showed increased expression. Ethylene treatment of unpollinated ovaries led to an increase in the SAMS1 mRNA level. However, SAMS2 expression remained unchangeable after ethylene treatment, indicating that SAMS2 induction during ovary senescence was not ethylene dependent. SAMS mRNAs were localized by in situ hybridization at the endocarp of developing fruits and in the ovules of senescing ovaries. Our results indicate that the transcriptional regulation of SAMS genes is developmentally controlled in a specific way for each gene.

Aging↗
PubMed1996

Hormonal regulation of S-adenosylmethionine synthase transcripts in pea ovaries.

Two cDNA clones coding for S-adenosyl-L-methionine synthase (SAMs, EC 2.5.1.6) have been isolated from a cDNA library of gibberellic acid-treated unpollinated pea ovaries. Both cDNAs were sequenced showing a high degree of identity but coding for different SAMs polypeptides. The presence of two SAMs genes in pea was further confirmed by Southern analysis. Expression of the SAMs genes in the pea plant was found at different levels in vegetative and reproductive tissues. We characterized the expression levels of SAMs genes during the development or senescence of pea ovaries. Northern analysis showed that transcription of SAMs genes in parthenocarpic fruits was upregulated by auxins in the same manner as in fruits from pollinated ovaries. In both pollinated and 2,4-dichlorophenoxyacetic acid-treated ovaries, and benzyladenine, although able to induce parthenocarpic development, did not affect SAMs mRNA levels. These data are consistent with an active participation of auxins in the upregulation of SAMs during fruit setting in pea and suggest that, at the molecular level, parthenocarpic development of pea ovaries is different for gibberellin- and cytokinin-treated ovaries than for auxin-induced parthenocarpic biosynthesis since treatment of the ovaries with aminoethoxyvinylglycine resulted in a delay of senescence and prevention of SAMs mRNA accumulation. A possible mechanism for hormonal regulation of SAMs during ovary development is discussed.

Aging↗