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Biomedical subjects

H Barros

Publications and source records attributed to H Barros.

At least 19 recordsLinked to original sources
PubMed2006

On the presence of enriched amounts of 235U in hot particles from the terrestrial area affected by the Palomares accident (Spain).

The characterisation by ICP-MS of an isolated Pu-U hot particle originating from the nuclear weapons accident in Palomares (Spain) shows, for the first time, that its uranium content is highly enriched in (235)U. The enrichment has been confirmed by independent analyses of two surface soil samples collected in a heavily contaminated area close to the impact point of one of the bombs. This finding clarifies better the composition of the weapons involved in the accident and is of importance when the inventory of U and Pu in the contaminated area are to be calculated.

Environmental Monitoring↗
PubMed2006

How different is the dietary pattern in non-alcoholic steatohepatitis patients?

BACKGROUND/AIMS: This study aimed at evaluating whether patients with non-alcoholic steatohepatitis (NASH) had a specific dietary pattern and how it compared with data representative from the same geographical region individuals. SUBJECTS AND METHODS: Clinical, biochemical and anthropometrics: weight, height, body mass index (BMI) and waist circumference were collected in 45 NASH patients. Diet history was assessed using a validated semi-quantitative food frequency questionnaire, analysed with the Food Processor Plus, and was compared, after adjustment for BMI, with data from a sample of 856 free-living individuals, frequency matched for sex and age. RESULTS: Patients' mean age was 49.6+/-10.6 years, 26 F: 19 M, BMI: 31.2+/-5.0 kg/m2. Comparison of their diet history with control data (C) revealed that carbohydrate consumption was lower in patients (P): P-243.6+/-5.7 g vs. C-261.5+/-1.6 g, P<0.05, and most patients had very low fibre intake. Conversely, total fat consumption was higher in patients: P-79.7+/-1.7 g vs. 73.0+/-0.4, P<0.01. A significantly higher intake of n-6 fatty acids (P=0.003) and n-6/n-3 ratio was found in patients, P<0.001. CONCLUSIONS: Our results suggest that the quality and combination of carbohydrates and fat intake may be more relevant than their isolated amount; an increased fat intake with an excessive amount of n-6 fatty acids can be implicated in promoting necro-inflammation, and provides further grounds for individualized dietary therapy.

Adult↗
PubMed2005

Central obesity as a major determinant of increased high-sensitivity C-reactive protein in metabolic syndrome.

INTRODUCTION: Traditional cardiovascular risk factors such as central obesity, high blood pressure and insulin resistance, all constituents of metabolic syndrome, have been associated with increased levels of C-reactive protein (CRP). Therefore, this marker of low-grade inflammation may play a major role in the pathogenesis of cardiovascular diseases. In this study, data from a representative sample of urban adults was used to evaluate the association between CRP and metabolic syndrome, accounting for the type and number of its constituents. METHODS: Using random digit dialing, 1022 participants, aged 18-92 y, were selected. All participants completed a structured questionnaire comprising of information on social, demographic, behavioral and clinical aspects. Anthropometrics and blood pressure were recorded and a fasting blood sample collected. Metabolic syndrome was defined, according to the Third Report of the Expert Panel on Detection, Evaluation and Treatment of High Blood Cholesterol in Adults, as the presence of three or more of the following characteristics: waist circumference greater than 102 cm in men and 88 cm in women; triglyceride levels > or = 150 mg/dl; high-density lipoprotein cholesterol levels < 40 mg/dl in men and < 50 mg/dl in women; blood pressure > or = 130/85 mm Hg; and serum glucose > or = 110 mg/dl. High-sensitivity CRP was assessed by immunonephelometric assay. After excluding 65 participants with CRP > or = 10 mg/l, 957 subjects (599 women and 358 men) remained for analysis. Geometric means were compared after adjustment for age, sex, alcohol consumption and smoking. RESULTS: Higher mean levels of CRP (2.34 vs 1.36, P < 0.001) were observed when metabolic syndrome was present. Also, mean CRP levels were significantly higher in the presence of central obesity (2.45 vs 1.24, P < 0.001), high blood pressure (1.76 vs 1.12, P < 0.001), hypertriglyceridemia (2.17 vs 1.32, P < 0.001) and high fasting glucose (1.96 vs 1.46, P = 0.032). We found a significant increasing trend (P < 0.001) in mean levels of CRP as the number of features of metabolic syndrome increased. The major contributing features for high CRP levels were central obesity and high blood pressure. CONCLUSIONS: Present data show that increasing severity of metabolic syndrome is associated with increasing CRP. Additionally, we found that central obesity and high blood pressure are the most important determinants of the low-grade chronic inflammation present in metabolic syndrome.

Adolescent↗
PubMed2004

Trends of radionuclide sorption by estuarine sediments. Experimental studies using 133Ba as a tracer.

Sediments play an important (but still poorly understood) role in the dispersion and final fate of radionuclides and other hazardous materials in aquatic systems. Adopting an experimental point of view, the present work deals with the transfer of a radioactive tracer from water to sediments. Sediments and waters were sampled in the Odiel and Tinto estuaries (South-West Spain) with anthropogenic-enhanced 226Ra concentrations. 133Ba was used as a tracer since it is a gamma emitter and a good analogue of the environmental behaviour of 226Ra. Laboratory experiments have been carried out to quantify the uptake kinetics of 133Ba by sediments in aqueous suspensions and by sediment cores under a water column at rest. Depth distributions of 133Ba in sediments have been studied with different contact times and using sediment samples with different grain sizes. The results reveal an important and fast uptake by suspended sediments (up to 40% in 10 min with a 20 g l(-1) suspension) and sediment cores (up to 70% in a few minutes). The kinetics of the uptake by suspended sediments could be reasonably described by a model of two parallel and reversible reactions followed by a weakly-reversible reaction. The total uptake and the rate of reaction decreased with the increment of grain size. Furthermore, uptake following diffusion through the interstitial water was hardly detectable beyond 1 cm depth. For the case with more experimental results, the depth distribution could be reasonably described by the analytical solution based on the use of an effective diffusion coefficient (4.2 x 10(-12) m2 s(-1)) and the measured intrinsic distribution coefficient (kd = 63 +/- 6 l kg(-1)).

Barium↗
PubMed2004

Experimental and modelling study on the uptake and desorption kinetics of 133Ba by suspended estuarine sediments from southern Spain.

Dispersion of pollutants in aquatic environments depends on their uptake by suspended solids. This work deals with the uptake kinetics of 133Ba (gamma-emitter and a good analogue of 226Ra) by suspended estuarine sediments (which can be resuspended into the water column under certain conditions). This study presents a wide set of tracing experiments, including second tracing, decantation and desorption processes. The purpose is to characterize 133Ba uptake by sediments and to investigate the use and limitations of box models in order to describe the uptake kinetics. Water and sediment samples were collected in the Huelva estuary (Spain), where environmental 226Ra concentrations have been increased by two phosphate fertilizer industries. Samples were characterized by granulometric, organic carbon content, cation exchange capacity and XRF-EP analyses. Results revealed three-step kinetics, with characteristic times of minutes, hours and days. These results enabled the selection and calibration of a suitable box model and facilitated the testing of its use as a fully predictive tool.

Barium Radioisotopes↗
PubMed2004

The importance of recording physical and chemical variables simultaneously with remote radiological surveillance of aquatic systems: a perspective for environmental modelling.

Modern nuclear metrological tools allow the remote surveillance of the radiological status of the aquatic systems, providing an important advance in the protection of the environment. Nevertheless, the significance of the radiological data could be highly improved through simultaneous recording of physical and chemical variables that govern the behaviour and bioavailability of radionuclides in these aquatic systems. This work reviews some of these variables from the point of view of the environmental modelling. The amount, nature and dynamics of the suspended loads and bottom sediments strongly influence the behaviour of particle-reactive radionuclides. The kinetics of this process has a very fast component, as it is shown from our recent studies with 241Am, 239Pu and 133Ba in several aquatic systems from southern Spain. Changes in pH, temperature and in the electrical conductivity are influencing the uptake kinetics and the final partitioning of the radioactivity. Water currents govern the radionuclide transport and dispersion. These points are illustrated with modelling exercises in the scenarios of the Suez Canal (Egypt) and the Härsvatten Lake (Sweden).

Biological Availability↗
PubMed2004

Food hypersensitivity in Portuguese adults.

OBJECTIVE: To describe the frequency and epidemiological features of self-reported food hypersensitivity in Portuguese adults. DESIGN: Cross-sectional. SETTING: Participants were selected by random digit dialing among residents of Porto. SUBJECTS: In total, 659 individuals over 39 y were asked to recall the occurrence of food hypersensitivity, and to describe the most serious episode. The adoption of eviction diets and previous medical diagnosis of food allergy were recorded, and recent dietary intake was evaluated using a validated food frequency questionnaire. RESULTS: Self-reported food allergy was more frequent in women than men (7.3 vs 1.9%, P<0.01) and decreased with age. Age- and sex-standardized (European population > or =40 y) prevalence of food hypersensitivity was 4.8% (95% CI 3.4-6.9%). Most subjects (67.6%) referred allergy to a single food, fresh fruits being the more frequently incriminated (25%). Approximately 90% that reported food allergy declared the adoption of eviction diets, although 53% in fact ingested the incriminated foods during the previous year. CONCLUSIONS: The adult prevalence of food hypersensitivity in Porto is one of the lowest observed worldwide, probably reflecting specificities of the genetic make-up and dietary patterns of our population.

Adult↗
PubMed2004

Price and consumption of tobacco in Spain over the period 1965-2000.

Changes in cigarette price have had an appreciable impact on smoking prevalence in several countries. We analysed the price elasticity of demand for cigarettes (effect of price of cigarettes on tobacco consumption) between 1965 and 2000 in Spain. For total consumption of cigarettes, a 1% increase in price is associated with a 0.19% decrease of consumption (price elasticity of -0.19; P<0.01). The real price of blond cigarettes was significantly and inversely associated with blond cigarette consumption: on average, smoking prevalence decreased 1.25% for a 1% increase in the real price of cigarettes (significant price elasticity of -1.25). For black cigarettes we found a lower but still high and significant elasticity of -0.61. There is an inverse relation between price and consumption of cigarettes in Spain, indicating that interventions at the economic level (such as real increases in prices) may have an important public health impact in tobacco control.

Adult↗
PubMed2004

Regional trends in Portuguese gastric cancer mortality (1984-1999).

The international decline in gastric cancer is mainly attributed to improved socio-economic conditions. However, some southern and eastern European countries showed slower and later decline, reflecting a less favourable general environment The same probably applies to regional differences within countries, making national indicators potentially misleading. Fitting log-linear Poisson models we compared trends in gastric cancer mortality (1984-1999) across 18 Portuguese regions. Pearson correlation coefficients were computed to assess the regional association between decline in cancer mortality and baseline cancer mortality and variation in indices of social development and medical care. National gastric cancer mortality changed -2.0% year in men and -2.2% year in women. The regional yearly variation in mortality ranged from -3.5% [95% confidence interval (CI) -4.5 to -2.5] to -0.6% (95% CI -1.4 to 0.2) in men, and from -3.7% (95% CI -4.8 to -2.7) to -0.8% (95% CI -1.6 to 0.0) in women. Regional variation was not significantly associated with baseline gastric cancer mortality (r = 0.18, P = 0.47), but with the variation in post-neonatal mortality (r = 0.59, P = 0.01). In Portugal, gastric cancer shows a wide regional variation in frequency trends. The correlation with known indicators of social and economic development indicates that future improvement in gastric cancer rates is expected in parallel with a more widespread development.

Adult↗
PubMed2004

Influence of individually estimated portion size on the assessment of nutritional risk in colorectal cancer in Portugal.

We evaluated the influence of individually estimated portion sizes on the estimate of nutrient related risk of colorectal cancer, using data from a Portuguese hospital based case-control study on diet and colorectal cancer. A total of 100 patients with colorectal adenocarcinoma (aged 15-92 years) and 211 controls (aged 36-89 years) were included. Two data sets were created for nutrient analysis, the first one allowed estimates of food intake using data on portion size as collected with visual aids during the interview. The second estimate substituted respondents' estimate with a standard portion size, as used in the semi-quantitative (SQ) food frequency approach. The two analytic approaches yielded similar energy and nutrient intakes in cases and controls. The percent range of concordance is acceptable, in the same quartile varying from 44 to 82% (mean: 56%) and very good in the same or adjacent (+/-1) quartile (mean: 91%, range: 85-97%). The two estimates lead to a similar pattern of multivariate odd's ratio, however the SQ estimates resulted in more significant findings. We conclude that little extra information is gained by including individual portion size information when assessing diet-related risk of colorectal cancer.

Adenocarcinoma↗
PubMed2004

Amiodarone and optic neuropathy.

PURPOSE: To investigate the clinical, perimetric, contrast sensitivity and visual evoked potentials findings in patients on longterm treatment with amiodarone. METHODS: We enrolled 14 patients (age range 47-78 years, mean age 62.7 years) on chronic amiodarone therapy (mean cumulative dose of 519 g), and 14 age-matched control subjects. Participants were submitted to ophthalmological examination, kinetic visual field testing (Goldmann), standard achromatic automated perimetry (central 30-2, Humphrey), computerized isoluminant chromatic contrast sensitivity (CCS) and pattern visual evoked potentials evaluation (VEP). Data from baseline, 6-month and 1-year follow-up examinations were analysed. The main outcome measures were: initial and final corrected visual acuity; corneal, optic disc and fundus abnormalities; mean deviation (MD) and pattern standard deviation (PSD) central 30-2 perimetry parameters; visual field loss on kinetic perimetry; indices of CCS (tritan, protan and deutan axes), and pattern VEP latency (L-VEP) and VEP amplitude (a-VEP). RESULTS: We found a statistically significant difference between the patients and controls' baseline L-VEP and a-VEP measurements (p < 0.001). We found no significant correlation between prolonged L-VEP and duration of amiodarone use (r = 0.07). After a 1-year follow-up, we evidenced an average increment in L-VEP of 1.96 ms and a-VEP measurements showed a decline of 0.69 micro V. In cumulative dose-specific analyses, mean differences between baseline and 12-month L-VEP measurements were more evident in those taking higher than 200 g cumulative amiodarone doses (p = 0.03). We found abnormal tritan CCS results in 19 eyes (68%). Of these, four eyes belonged to patients with no ocular disease (diabetes, cataracts). No significant differences were observed between the baseline and 12-month clinical eye examinations, central 30-2 perimetry and CCS results. CONCLUSION: We found a significant prolongation in pattern L-VEP and a significant reduction in pattern a-VEP in patients on longterm treatment with amiodarone compared to control subjects. Nevertheless, current data are insufficient to recommend appropriate methods of visual screening.

Aged↗
PubMed2003

[Human serum alcaline phosphatase and ageing].

BACKGROUND: In experimental ageing models an inverse relationship between age and alkaline phosphatase activity has been observed. OBJECTIVE: To characterize serum levels of alkaline phosphatase activity in humans according to age and gender. METHODS: Serum alkaline phosphatase was determined in a random sample of 203 community dwellers aged 40 or more years. RESULTS: In men (n=87) total serum alkaline phosphatase markedly increased from the 5th to the 6th decade and then stabilized. For women (n=116) there was a slight increase in total serum alkaline phosphatase from the 5th to the 6th decade, followed by a bend upward after 69 years of age. There was a significant positive correlation between total serum alkaline phosphatase and age for the whole population. CONCLUSIONS: Serum alkaline phosphatase activity appears as a biomarker of age in humans, similarly to what has been described for experimental animal models.

Adult↗
PubMed2003

Prevalence and determinants of obesity in an urban sample of Portuguese adults.

OBJECTIVE: To evaluate the prevalence and the determinants of obesity, and the associated cardiovascular risk factors in a random sample of non-institutionalised adults. DESIGN: Cross-sectional study. SUBJECTS: A random sample of 1436 habitants of Porto (873 women and 563 men) aged 18-90 years. MEASUREMENTS: All participants answered a structured questionnaire comprising information on social, demographic, behavioural and clinical aspects. Anthropometric measures, blood pressure and fasting blood samples were obtained. Diet was assessed using a semi-quantitative food-frequency questionnaire, and physical activity was evaluated using a questionnaire exploring all professional, domestic and leisure-time activities. When the body mass index was > or =30 kg/m2, the subject was considered as 'obese'. Proportions were age adjusted for the European population. Odds ratios and 95% confidence intervals were computed using unconditional logistic regression. RESULTS: The prevalence of obesity was significantly higher in women (26.1%) than men (13.9%). Regardless of gender, obesity increased with age, decreased with education, and was more frequent in married blue-collar workers and unemployed subjects. Smoking was more prevalent in subjects of normal weight, and a higher proportion of those reporting no regular exercise were obese. In men, obesity prevalence increased with increasing quartiles of energy intake, but no such changes were found in women. Compared with subjects of normal weight, obese men showed a significantly higher prevalence of hypertension (53.3 vs 26.1%) and hypertriglyceridaemia (23.4 vs 9.0%). Also, hypertension (43.7 vs 30.7%), diabetes (7.6 vs 2.7%), hypertriglyceridaemia (27.1 vs 5.0%), and abnormal low-density lipoprotein (30.4 vs 21.4%) and high-density lipoprotein cholesterol concentration (15.0 vs 5.3%) were more frequent in obese women. CONCLUSION: Obesity is a major public health issue in urban Portuguese populations, and obese individuals have many features of metabolic syndrome. Education and relative deprivation are modifiable factors that are significantly associated with obesity. However, no clear-cut relationship was found between physical activity and energy intake.

Adolescent↗
PubMed2003

The role of adherence in tuberculosis HIV-positive patients treated in ambulatory regimen.

Adherence to antituberculosis treatment, a major determinant of outcome, is of special concern in human immunodeficiency virus (HIV)-positive patients. However, tuberculosis death in HIV-positive patients remains higher than in HIV-negative patients, regardless of adherence. To assess determinants for an unfavourable tuberculosis outcome (defined as no cure or death), and determinants for nonadherence to antituberculosis treatment, 70 HIV-positive patients with tuberculosis referred to an outpatient centre were studied. Patient outcome was compared according to HIV risk factors, other opportunistic diseases, antiretroviral drugs use, current i.v. drugs use, a methadone programme participation, tuberculosis features, treatment characteristics and adherence. Adherent and non-adherent patient characteristics were also compared. An unfavourable outcome occurred in 22.9% of patients and 32.9% were nonadherent with therapy. Nonadherence was the only independent determinant for an unfavourable outcome. Adherence was independently associated with current i.v. drug use, treatment complications and use of methadone. This study confirms that human immunodeficiency virus-infected patients, treated as outpatients, have high rates of nonadherence and that adherence is the strongest determinant for tuberculosis outcome. Independently of the current use of drugs, a methadone programme improves adherence to treatment.

Adult↗