Stability of risk factors for cardiovascular diseases in Portuguese children and adolescents from the Porto area.
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An important aspect of preventive medicine is to identify subjects at risk as soon as possible, so preventive strategies can be introduced at early ages. The justification for this strategy is twofold: firstly, the assumption that children maintain a particular high value of a risk factor for disease throughout life; and secondly, the assumption that lowering the level of the risk factor in early life will have a greater impact on the disease than will risk factor changes in later life. In epidemiology the analysis of such factors over time is referred to as tracking. Tracking analysis has been applied to risk factors for cardiovascular diseases (CVD) in pediatric years. The aims of this study were: I) to analyze the stability of biological risk factors [high blood pressure (BP), high percentage of fat mass (%FM) and high total cholesterol (TC)] and lifestyle risk factors [low physical activity index (PAI)] in isolation; and II) to analyze the stability of zero, one, two or three biological risk factors. There were two evaluations in 692 children and adolescents (325 boys and 367 girls), aged between 8 and 15 years. The quartiles, adjusted for age and gender, were the criterion used to identify subjects with biological risk factors (fourth quartile) and with lifestyle risk factors (first quartile) for CVD. The stability was calculated through the relative frequency of subjects who maintained or changed quartile between the two evaluations. There is stability for biological risk factors as well as for behavioral and/or lifestyle risk factors. However, the highest stability is seen in biological risk factors. (+info)
Effects of Eucalyptus plantations on detritus, decomposers, and detritivores in streams.
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Vast areas of the Iberian Peninsula are covered by monocultures of the exotic tree Eucalyptus globulus. Given that (1) leaf litter produced in the riparian areas is the main energy source for small streams, and (2) trees differ in their nutrient content, chemical defenses, and physical attributes, eucalypt plantations have the potential to affect the biology of streams. Research teams from the University of Coimbra and the University of the Basque Country have been addressing the potential effects of eucalypt plantations at several levels of study. Here we review the main conclusions of these investigations. Eucalypt plantations produced less litter than some deciduous forests. However, there were marked differences in timing of litterfall: litter production peaked during autumn in deciduous forests, whereas in the eucalypt forests it tended to peak in summer and to be more evenly distributed throughout the year. Despite these differences, the average standing stock of organic matter was higher in the eucalypt than in the deciduous forest. This may be attributed to (1) the occurrence of spates or heavy rain in autumn, the period of maximum litter fall in deciduous forests, and (2) bark accumulation in eucalypt forests. Because of differences in leaf composition, the nutrient input in eucalypt forests seems to be lower than in deciduous forests. The rate of decomposition of eucalypt leaves was strongly dependent on nutrients in the water: in nutrient-poor waters it was slower than that of most other leaf species, whereas in nutrient-rich waters it can be as fast as alder--a fast-decaying species. The biomass and cumulative diversity of aquatic hyphomycetes colonizing leaves did not differ between eucalypt and other native leaf species, but fungal sporulation generally peaked 2 weeks later on eucalypt leaves. This lag disappeared when lipids (but not polyphenolics) were chemically removed from eucalypt leaves. Similarly, addition of eucalypt oils to culture media retarded or suppressed fungal growth. Streams bordered by Eucalyptus had lower diversity of fungal spores (but similar spore densities) in Portugal; less consistent patterns were found in similar experiments in Spain. Eucalyptus leaves proved to be poor food for shredders. Under laboratory conditions leaves of Eucalyptus ranked low in food selection experiments using native shredders. The same shredders failed to grow and died when fed exclusively eucalypt leaves. The removal of oils from eucalypt leaves resulted in increased feeding rates, whereas the transfer of oils to alder leaves resulted in decreased feeding rates. The effect of eucalypt plantations on stream invertebrate communities is not very consistent. In nutrient-poor waters, fewer invertebrates colonized eucalypt than alder leaves, but this effect was mitigated after a microbial conditioning period in nutrient-rich waters. Portuguese streams bordered by Eucalyptus had lower numbers of invertebrates than streams surrounded by deciduous forests. In Spanish streams differences were less marked and nonexistent when looking at the composition of the communities, which change more from year to year than from site to site. Most of the eucalypt streams studied in Portugal and Spain dried up in summer, a fact that might reflect an increase in soil hydrophobity produced by Eucalyptus plantations. The very short planting-to-harvest period of eucalypt plantations results in additional impacts, such as soil loss, siltation of streams, or reduced amounts of woody debris in stream channels, which affects their capacity to retain leaf-litter, as well as the availability of habitat for invertebrates and fish. The studies by the Portuguese and Spanish research teams confirm the importance of maintaining riparian buffer strips to reduce human impact on streams and rivers. (+info)
Genetic characterization of southwestern European bovine breeds: a historical and biogeographical reassessment with a set of 16 microsatellites.
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The origin of Iberian cattle has been suggested by some authors to be the product of European and north African cattle entrances during the last few thousands of years. However, these hypotheses were mainly based on morphological similarities. This study analyzed 889 unrelated individuals from 15 representative Iberian breeds and 3 French breeds for 16 microsatellite loci. Statistical tests were used to calculate interpopulation genetic distances (D(A)) and principal components analysis (PCA). To visualize the geographical distribution of the genetic differentiation between Iberian cattle breeds, data from the PCA analysis were used to construct synthetic maps. Genetic similarity among neighboring Iberian breeds is mainly caused by gene flow. However, recent demographic fluctuations and reproductive isolation in Alistana, Mirandesa, and Tudanca has increased genetic drift, which may be the main cause for the relatively high differentiation of these populations. The synthetic maps constructed with the first and second PCs revealed (1) a large differentiation between Northern Iberian breeds rather than between more geographically distant breeds, and (2) a clear east-west gradient that may be related with the model of demic diffusion of agriculture. Finally, we detected no strong evidence for an African genetic influence in the Iberian cattle breeds analyzed in this study. (+info)
Impact of cardiovascular risk factors in an urban sample of Portuguese adults according to the Framingham risk prediction models.
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OBJECTIVES: To estimate the 10-year risk of coronary heart disease (CHD) according to the Framingham risk prediction models and to assess the impact of major risk factors in an urban sample of Portuguese adults. METHODS: We surveyed 938 non-institutionalized adults aged 40 to 74 years, recruited by random digit dialing. A fasting venous blood sample was collected to measure glucose, total cholesterol and high-density-lipoprotein (HDL) cholesterol. Blood pressure was measured and a resting 12-lead ECG registered. Sixty-eight individuals (7.2%) were excluded due to prevalent CHD, according to self-reported information and/or ECG. Data on the remaining 532 women and 338 men at risk were used for analysis. For each participant we calculated the 10-year risk using the Framingham risk tables. RESULTS: In this community-based sample, the expected 10-year cumulative incidence was estimated to be on average 19.3% for men and 9.5% for women. The factor with greatest impact was hypertension. Had this factor been altered such that individuals whose blood pressure was > or = 140/90 mmHg instead had high-normal blood pressure (130-139/85-89 mmHg), the risk of CHD would have been reduced to 15.7% in men and 7.3% in women. Thus, 18.6% and 23.2% of cases would have been avoided, respectively. The number of individuals in whom hypertension should be prevented to avoid one case of CHD was 15 among men and 25 among women. The impact of other risk factors expressed as a proportion of attributable cases was, in men and women respectively, 5.7% and 7.4% if none had diabetes; 12.4% and 3.2% if none smoked; 23.8% and 14.7% if total cholesterol were between 160 and 199 mg/dl instead of over 200 mg/dl; and 10.9% and 5.3% if HDL were above 45 mg/dl. If all participants did not smoke, did not have diabetes, had total cholesterol between 160 and 199 instead of over 200 mg/dl, HDL over 45 mg/dl and high-normal blood pressure instead of hypertension, the expected cumulative incidence would be 8.1% for men and 5.1% for women. This means that respectively 58.0% and 46.3% of cases would have been avoided. CONCLUSION: Blood pressure control in this population is the intervention with greatest impact on CHD prevention. Given the tendency for risk factors to cluster and to interact, we can expect to achieve even greater success with multifactorial interventions. (+info)
Incidence and prevalence of hypercholesterolemia in Portugal: a systematic review. Part I.
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INTRODUCTION: Over 50% of the mortality and disability caused by ischemic heart disease and stroke could be avoided by controlling individual risk factors (hypertension, hypercholesterolemia, smoking and obesity). The ignorance of the extent and impact of hypercholesterolemia (HC) in Portugal prompted us to undertake this systematic review of the prevalence and incidence of hyperlipidemia in Portugal, based exclusively on work published nationally. METHODS: We included every study published in the country that could provide data on the prevalence or incidence of hypercholesterolemia. The search strategy included an electronic search of national and international biomedical databases (Medline, Index Revistas Medicas Portuguesas, the Portuguese Directorate-General for Health and the Portuguese National School of Public Health), screening of reference lists from the individual studies, and personal contacts with institutions, groups and authors (such as the Portuguese Foundation of Cardiology). The data--recorded in electronic format--was collected independently by two of the authors (JC and MB), with consensus achieved with a third (AVC) when there were differences in the study coding. RESULTS: We could only identify one paper on the incidence of HC in Portugal, which gave an incidence of 559 new cases per 100,000 inhabitants, increasing with age up to 54 years for men and 64 years for women. There was a higher incidence in men than in women up to the age of 54, but at more advanced ages this relationship was reversed. Prevalence studies on HC included 53,445 individuals overall, with sample size lower than 1000 in most of the individual studies. The most frequently used criterion for HC was > 200 mg/dL, with the mean level being higher in most studies. We calculated the mean prevalence for several cut-off points (190 mg/dL: 63.8%; 200 mg/dL: 56.7%; 240 mg/dL: 31.7%; 250 mg/dL: 21%). Due to the heterogeneity of the data, these results are to be interpreted with caution, even though they are consistent across individual studies. The prevalence of hypertriglyceridemia (HTG) was highly variable across studies. Most of them used a baseline criterion of 150 mg/dL (11-26%) or 200 mg/dL (8.9-33.9%). CONCLUSIONS: Despite the obvious heterogeneity and a certain paucity of studies, we found consistent results concerning the prevalence of hypercholesterolemia in Portugal, and we can state that this constitutes a serious health problem in our country. The prevalence of hypercholesterolemia was higher than that of arterial hypertension in our population. The results of this study should serve as a basis for a commitment to action from the health authorities and health professionals as well as patients. (+info)
Hormonal control of swimbladder sonic muscle dimorphism in the Lusitanian toadfish Halobatrachus didactylus.
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The swimbladder and associated sonic muscle of the Lusitanian toadfish Halobatrachus didactylus increase in size throughout life and are, respectively, 25% and 30% larger in type I (nest-holder) males than females, which may generate sexual differences in sound production. Sexual dimorphism in swimbladder is also evident in the morphological features of sonic muscle fibers. During the breeding season, type I males have smaller myofibril contracting zones surrounded by larger sarcoplasm areas compared with females, possibly an adaptation to speed and fatigue resistance for the production of long mating calls. Type II (floater) males show characteristics that are intermediate, but statistically not significantly different, between type I males and females. Six weeks after castration and androgen (testosterone and 11-ketotestosterone) replacement in type I and type II males there were no alterations either in swimbladder mass or fiber morphology. However, 17beta-estradiol induced a significant decrease in swimbladder mass and sarcoplasm area/myofibril area ratio. Six months after castration there was a clear reduction in the seasonal swimbladder hypertrophy in males and induction of sonic fiber morphological characteristics that resemble those occurring in females (low sarcoplasm area/myofibril area ratio). These results suggest that testicular factors are required to initiate sonic muscle hypertrophy and type I sonic fiber phenotype in H. didactylus, but a specific involvement of androgens has not been completely clarified. (+info)
Incidence and prevalence of hypercholesterolemia in Portugal: a systemic review. Part II.
(63/873)
INTRODUCTION: Over 50% of the mortality and disability caused by ischemic heart disease and stroke could be avoided by controlling individual risk factors (hypertension, hypercholesterolemia, smoking and obesity). The ignorance of the extent and impact of hypercholesterolemia (HC) in Portugal prompted us to undertake this systematic review of the prevalence and incidence of hyperlipidemia in Portugal, based exclusively on work published nationally. METHODS: We included every study published in the country that could provide data on the prevalence or incidence of hypercholesterolemia. The search strategy included an electronic search of national and international biomedical databases (Medline, Index Revistas Medicas Portuguesas, the Portuguese Directorate-General for Health and the Portuguese National School of Public Health), screening of reference lists from the individual studies, and personal contacts with institutions, groups and authors (such as the Portuguese Foundation of Cardiology). The data--recorded in electronic format--was collected independently by two of the authors (JC and MB), with consensus achieved with a third (AVC) when there were differences in the study coding. RESULTS: We could only identify one paper on the incidence of HC in Portugal, which gave an incidence of 559 new cases per 100,000 inhabitants, increasing with age up to 54 years for men and 64 years for women. There was a higher incidence in men than in women up to the age of 54, but at more advanced ages this relationship was reversed. Prevalence studies on HC included 53,445 individuals overall, with sample size lower than 1000 in most of the individual studies. The most frequently used criterion for HC was > 200 mg/dL, with the mean level being higher in most studies. We calculated the mean prevalence for several cut-off points (190 mg/dL: 63.8%; 200 mg/dL: 56.7%; 240 mg/dL: 31.7%; 250 mg/dL: 21%). Due to the heterogeneity of the data, these results are to be interpreted with caution, even though they are consistent across individual studies. The prevalence of hypertriglyceridemia (HTG) was highly variable across studies. Most of them used a baseline criterion of 150 mg/dL (11-26%) or 200 mg/dL (8.9-33.9%). CONCLUSIONS: Despite the obvious heterogeneity and a certain paucity of studies, we found consistent results concerning the prevalence of hypercholesterolemia in Portugal, and we can state that this constitutes a serious health problem in our country. The prevalence of hypercholesterolemia was higher than that of arterial hypertension in our population. The results of this study should serve as a basis for a commitment to action from the health authorities and health professionals as well as patients. (+info)
Molecular epidemiology of Salmonella enteritidis phage type 1b and 6a isolates in Portugal.
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Salmonella enterica serotype Enteritidis is an important serovar comprising 76 % of Salmonella isolates in Portugal in 2001. For better understand the epidemiology of salmonellosis, a total of 47 isolates of S. Enteritidis phage type (PT) 1b and 6a were analysed by pulsed-field gel electrophoresis (PFGE) and genomic DNA was subjected to macro restriction with XbaI. For PT 1b isolates, only three different patterns were observed, and PT6a showed a total of 10 digestion patterns. Curiously, the main pattern among PT1b isolates seams quite similar to main pattern of PT6a isolates, but when the two patterns were analysed with Bionumerics, we observed that they exhibited some differences. It was concluded that, in 2001, there was one predominant pattern for PT1b and PT6a and, possibly, we were in presence of clonal strains that exists all over the country. (+info)