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F Ballester

Publications and source records attributed to F Ballester.

At least 55 records · Page 3Linked to original sources
PubMed2000

Monte Carlo calculations of dose rate distributions around the Amersham CDCS-M-type 137Cs source.

The Amersham CDCS-M-type 137Cs stainless-steel encapsulated source is widely used in low dose rate brachytherapy with manual afterloading. However there is a need for more accurate dosimetry data. In this study we present Monte Carlo calculations of absolute dose rate in water around this source using the Monte Carlo code GEANT, discuss dosimetric features of these data, and compare them with Krishnaswamy's results for 137Cs intracavitary sources. Dose rate distributions are presented in the form of along-away tables and in the TG43 formalism. Simulated absolute dose rate values can be used as benchmark data to verify the treatment planning system calculation results or directly as input data for treatment planning. Best-fit values of attenuation coefficients suitable for use in Sievert integral type calculations have been derived comparing dose rate distributions calculated using this algorithm with those obtained from Monte Carlo calculations.

Algorithms↗
PubMed2000

Serum concentrations of hexachlorobenzene in family members of workers in an electrochemical factory.

OBJECTIVES: This study analyzed the effect of living in the same household with a worker employed in an electrochemical factory on the hexachlorobenzene (HCB) concentrations of serum in the general population of Flix, Spain. METHODS: A total of 608 subjects from the general population (response rate 42%) completed a questionnaire about residence, occupation, life-styles, and medical history and provided blood samples. Among them, 412 had never worked in the electrochemical factory. Information about the occupation of the family members was completed, and the subjects were classified with the degree of relationship with the worker having been taken into account. A multiple linear regression analysis was conducted to model HCB serum for nonfactory workers. RESULTS: Having a spouse who worked in the factory was associated with elevated HCB concentrations in serum. The adjusted relative increases were 1.28 (P=0.0004) and 1.23 (P=0.0022) times the corresponding value of people not living with workers of the factory, respectively for spouses of current and past workers. Relatives other than spouses did not show any increase. CONCLUSIONS: The results of this study suggest that, among nonworkers, living with a worker of the electrochemical factory in Flix is associated with an increase in concentrations of HCB in blood. These findings may suggest a source of exposure to HCB that has thus far not been studied and that could be important in populations not occupationally exposed to organochlorines.

Adult↗
PubMed2000

[Rhabdomyoma in the adult].

Rhabdomyoma in adults is a rare benign tumor of the skeletal muscle that usually arises in the head and neck region. We report a new case of this rare tumor located in the tongue. The treatment, evolution, and anatomo-pathologic findings are described.

Humans↗
PubMed1999

Asthma visits to emergency rooms and soybean unloading in the harbors of Valencia and A Coruña, Spain.

Soybean unloading in the harbor of Barcelona, Spain, has been associated with large increases in the numbers of asthma patients treated in emergency departments between 1981 and 1987. In this study, the association between asthma and soybean unloading in two other Spanish cities, Valencia and A Coruña, was assessed. Asthma admissions were retrospectively identified for the period 1993-1995, and harbor activities were investigated in each location. Two approaches were used to assess the association between asthma and soybean unloading: One used unusual asthma days (days with an unusually high number of emergency room asthma visits) as an effect measure, and the other estimated the relative increase in the daily number of emergency room visits by autoregressive Poisson regression, adjusted for meteorologic variables, seasonality, and influenza incidence. No association between unusual asthma days and soya unloading was observed in either Valencia or A Coruña, except for one particular dock in Valencia. When the association between unloaded products and the daily number of emergency asthma visits was studied, a statistically significant association was observed for unloading of soya husk (relative risk = 1.50, 95% confidence interval 1.16-1.94) and soybeans (relative risk = 1.31, 95% confidence interval 1.08-1.59) in A Coruña. In Valencia, a statistical association was found only for the unloading of soybeans at two particular docks. Although these findings support the notion that asthma outbreaks are not a common hidden condition in most harbors where soybeans are unloaded, the weak associations reported are likely to be causal. Therefore, appropriate control measures should be implemented to avoid soybean dust emissions, particularly in harbors with populations living in the vicinity.

Air Pollutants↗
PubMed1999

[The patterns of use and factors associated with the patient admission of hospital emergencies for asthma and chronic obstructive pulmonary disease].

The aim of this study was to describe the epidemiological characteristics of emergencies caused by asthma and chronic obstructive pulmonary disease (COPD) at the Hospital Clínico Universitario of Valencia (Spain) and to analyze factors related to hospital admissions for the same causes. Emergency room medical records for 1993 to 1995 of patients older than 14 years of age were examined to identify those due to asthma or COPD, according to established protocol. Demographic variables were described, followed by Poisson regression analysis of time and seasonal factors affecting emergencies. Factors related to hospital admission were analyzed by logistic regression, taking into account age group, sex, place of residence, and the year, month, day and hour of emergency room arrival. Asthma patients amounted to 1% of emergencies, while COPD patients accounted for 2%. The admission rate for women with asthma was higher than for men (F/M ratio = 0.78), whereas the rate for men with COPD was higher than for women (F/M ratio = 3.14). The largest age groups with asthma emergencies included young people aged 15 to 24 years old and those over 60. Hospital admissions or transfers to other hospitals were ordered for 17.4% of asthma patients and 38.8% of COPD patients. Nearly a third of COPD patients and a fifth of asthma patients were readmitted within the ten days following the first emergency. Clear temporal patterns of COPD emergency were observed for month (most occurring in winter), day of the week (most on Monday) and hour of the day (most during daytime hours, with fewer at midday). The time patterns were less evident for asthma emergencies, although the likelihood of admission because of asthma varied by month and day of the week. Emergency room records may be useful for studying the patterns of respiratory disease presentation. Other possible uses are epidemiologic monitoring and evaluation of health care quality.

Adolescent↗
PubMed1999

Spread of amikacin resistance in Acinetobacter baumannii strains isolated in Spain due to an epidemic strain.

Sixteen amikacin-resistant clinical Acinetobacter baumannii isolates from nine different hospitals in Spain were investigated to determine whether the high incidence of amikacin-resistant A. baumannii was due to the dissemination of an amikacin-resistant strain or to the spread of an amikacin resistance gene. The epidemiological relationship studied by repetitive extragenic palindromic PCR and low-frequency restriction analysis of chromosomal DNA showed that the same clone was isolated in eight of nine hospitals, although other clones were also found. The strains were studied for the presence of the aph(3')-VIa and aac(6')-I genes, which encode enzymes which inactivate amikacin, by PCR. All 16 clinical isolates had positive PCRs with primers specific for the amplification of the aph(3')-VIa gene, whereas none had a positive reaction for the amplification of the aac(6')-I gene. Therefore, the high incidence of amikacin resistance among clinical A. baumannii isolates in Spain was mainly due to an epidemic strain, although the spread of the aph(3')-VI gene cannot be ruled out.

Acinetobacter↗
PubMed1998

Glomerular basement membrane. Identification of a novel disulfide-cross-linked network of alpha3, alpha4, and alpha5 chains of type IV collagen and its implications for the pathogenesis of Alport syndrome.

Glomerular basement membrane (GBM) plays a crucial function in the ultrafiltration of blood plasma by the kidney. This function is impaired in Alport syndrome, a hereditary disorder that is caused by mutations in the gene encoding type IV collagen, but it is not known how the mutations lead to a defective GBM. In the present study, the supramolecular organization of type IV collagen of GBM was investigated. This was accomplished by using pseudolysin (EC 3.4.24.26) digestion to excise truncated triple-helical protomers for structural studies. Two distinct sets of truncated protomers were solubilized, one at 4 degrees C and the other at 25 degrees C, and their chain composition was determined by use of monoclonal antibodies. The 4 degrees C protomers comprise the alpha1(IV) and alpha2(IV) chains, whereas the 25 degrees C protomers comprised mainly alpha3(IV), alpha4(IV), and alpha5(IV) chains along with some alpha1(IV) and alpha2(IV) chains. The structure of the 25 degrees C protomers was examined by electron microscopy and was found to be characterized by a network containing loops and supercoiled triple helices, which are stabilized by disulfide cross-links between alpha3(IV), alpha4(IV), and alpha5(IV) chains. These results establish a conceptual framework to explain several features of the GBM abnormalities of Alport syndrome. In particular, the alpha3(IV). alpha4(IV).alpha5(IV) network, involving a covalent linkage between these chains, suggests a molecular basis for the conundrum in which mutations in the gene encoding the alpha5(IV) chain cause defective assembly of not only alpha5(IV) chain but also the alpha3(IV) and alpha4(IV) chains in the GBM of patients with Alport syndrome.

Animals↗
PubMed1998

Association between hospital emergency visits for asthma and air pollution in Valencia, Spain.

OBJECTIVE: To assess the short term effect of concentrations of black smoke, sulphur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3) in ambient air on emergency room visits for asthma in the city of Valencia, Spain during the period 1994-5. METHODS: Ecological study with time series data and application of Poisson regression. Associations between number of daily emergency visits in a city's hospital and concentrations of air pollutants were analysed taking into account potential confounding factors by the standardised protocol of the air pollution and health: a European approach (APHEA) project. RESULTS: Mean (range) daily number of emergency room visits for asthma was 1 (0-5). Concentrations of all pollutants studied remained within current air quality standards. The association between an increase of 10 micrograms/m3 in ambient air pollution and asthma, measured as a relative risk (RR) of emergency visits, was significant for NO2 24 hour mean (lag 0, RR 1.076, 95% confidence interval (95% CI) 1.020 to 1.134), NO2 hour maximum (lag 0, RR 1.037, 95% CI 1.008 to 1.066), and O3 hour maximum (lag 1, RR 1.063, CI 95% 1.014 to 1.114). The association was not significant for SO2 or for black smoke during the period analysed. The effects were not significantly different for the time of year, cold months (November to April), or warm months (May to October). CONCLUSIONS: Current concentrations of ambient air pollution in Valencia are significantly associated with emergency room visits for asthma. This association is high and more consistent for NO2 and O3 than for particulate matter and SO2 (classic pollutants).

Adolescent↗
PubMed1997

Mortality as a function of temperature. A study in Valencia, Spain, 1991-1993.

BACKGROUND: Increased mortality is associated with both very low and very high ambient temperatures. This study assesses the relationship between daily numbers of deaths and variations in ambient temperature within the city of Valencia. METHODS: The daily number of deaths from all causes (total deaths and only those occurring in people aged over 70), as well as those deaths from specific causes (e.g. cardiovascular and respiratory diseases, malignant tumours and all causes except external ones) occurring within the city of Valencia were related to the average daily temperature using autoregressive Poisson regression controlling for seasonality, day of the week, holidays, air pollution, influenza incidence, and humidity. Temperature was measured within the regression model as two complementary variables: 'Heat' and 'Cold'; also taken into account were their delayed effects up to 2 weeks after measurement. RESULTS: Graphical analysis revealed a relationship between temperature and mortality according to the time of year. For the cooler months (November-April), the temperature at which mortality was lowest was the 'minimum' (i.e. around 15 degrees C), while for the warmer months (May-October), it occurred at around 24 degrees C. Because of this, a stratified analysis was undertaken with different values for the 'Heat' and 'Cold' variables according to which of the two seasons was involved. During the colder months of the year, higher temperatures tended to exert a rapid influence on mortality and the lower temperatures a more delayed relation. During the hot season it is the heat variable which more clearly manifests an effect, and this is prolonged over the two following weeks. Variations also occur according to age and cause of death. The effect of temperature is greater in persons aged over 70 years of age, and it is also greater in cases of circulatory and respiratory diseases. CONCLUSIONS: A statistically significant association has been found between temperature and mortality. This relationship is not monotonic, but mortality increases in proportion to the variance in ambient temperature from a range of temperatures that varies from winter to summer.

Cardiovascular Diseases↗
PubMed1997

Monte Carlo calculation of dose rate distributions around 192Ir wires.

Monte Carlo calculations of absolute dose rate in liquid water are presented in the form of away-along tables for 1 and 5 cm 192Ir wires of 0.3 mm diameter. Simulated absolute dose rate values can be used as benchmark data to verify the calculation results of treatment planning systems or directly as input data for treatment planning. Best fit value of attenuation coefficient suitable for use in Sievert-integrals-type calculations has been derived based on Monte Carlo calculation results. For the treatment planning systems that are based on TG43 formalism we have also calculated the required dosimetry parameters.

Biophysical Phenomena↗
PubMed1996

Air pollution and mortality in Valencia, Spain: a study using the APHEA methodology.

STUDY OBJECTIVE: To assess the short term relationship between daily air pollution indicators (black smoke and sulphur dioxide (SO2)) and mortality in Valencia. DESIGN: This was an ecological study using time series data with application of Poisson regression. Daily variations in four selected outcome variables (total mortality, mortality in those over 70 years of age, and cardiovascular and respiratory mortality) were considered in relation to daily variations in air pollution levels for the period 1991-93. SETTING: The city of Valencia, Spain. MAIN RESULTS: The mean daily mortality was 17.5, and the average daily levels of air pollutants from the three monitoring stations included in the study were, 67.7 micrograms/m3 for black smoke, and 39.9 micrograms/ m3 for SO2. A significant positive association between black smoke and three of the four outcomes in the study was found. The estimated relative risk (RR) of dying corresponding to a 10 micrograms/m3 increase in mean daily black smoke over the whole period was 1.009 (95% confidence interval (95% CI): 1.003, 1.015). For mortality in the group aged more than 70 years and for cardiovascular mortality, the RRs were 1.008 (95% CI: 1.001, 1.016) and 1.012 (95% CI: 1.003, 1.022) respectively. The association with SO2 was less clear: it was only evident during the warm season. The estimated RRs in this case were 1.007 (95% CI: 0.999, 1.015) for total mortality, 1.009 (95% CI: 1.00, 1.21) for total mortality in those older than 70, and 1.012 (95% CI: 0.995, 1.026) for cardiovascular deaths. No significant association was found between mortality from respiratory diseases and either of the two pollutants. CONCLUSIONS: A positive relationship between air pollution and mortality was found in the short term, as has been shown in an important number of studies carried out elsewhere. Although the current levels of particulate air pollution in Valencia are not very high, they could have an effect on the number of premature deaths. Despite the fact that the association is weak, it is important at the public health level both because of the numbers of population exposed and the possibility of establishing control measures.

Adolescent↗
PubMed1995

Cutaneous phaeohyphomycosis caused by Alternaria longipes in an immunosuppressed patient.

Alternaria longipes was reported as the agent of a cutaneous infection in a patient with a neoplastic disease. The fungus has not been reported previously as causing disease in humans. It was distinguished by its rather small conidia with smooth or slightly verruculose walls and a pale brown beak which rarely extended into a secondary conidiophore. In vitro inhibitory activities of amphotericin B, ketoconazole, itraconazole, and miconazole were shown.

Alternaria↗