Lluís Jover

Endothelial dysfunction in pulmonary arteries of patients with mild COPD

To investigate whether endothelial dysfunction of pulmonary arteries (PA) is present in patients with mild chronic obstructive pulmonary disease (COPD) and to what extent it is related to the morphological abnormalities of PA, we studied 41 patients who underwent lung resection. Patients were divided into the following groups: nonsmokers ( n = 7), smokers with normal lung function ( n = 13), and COPD ( n = 21). Endothelium-dependent relaxation mediated by nitric oxide was evaluated in vitro in PA rings exposed to cumulative concentrations of acetylcholine (ACh) and ADP. Structural abnormalities of PA were assessed morphometrically. PA of COPD patients developed lower maximal relaxation in response to ADP than both nonsmokers and smokers ( P < 0.05 each) and a trend to reduced relaxation in response to ACh ( P = 0.08). Maximal relaxation to ADP correlated with the degree of airflow obstruction ( r = 0.48, P < 0.01). Morphometrical analysis of PA revealed thicker intimas, especially in small arteries, in both smokers and COPD compared with nonsmokers ( P < 0.05 each). We conclude that endothelial dysfunction of PA is already present in patients with mild COPD. In these patients, as well as in smokers with normal lung function, small arteries show thickened intimas, suggesting that tobacco consumption may play a critical role in the pathogenesis of pulmonary vascular abnormalities in COPD.To investigate whether endothelial dysfunction of pulmonary arteries (PA) is present in patients with mild chronic obstructive pulmonary disease (COPD) and to what extent it is related to the morphological abnormalities of PA, we studied 41 patients who underwent lung resection. Patients were divided into the following groups: nonsmokers (n = 7), smokers with normal lung function (n = 13), and COPD (n = 21). Endothelium-dependent relaxation mediated by nitric oxide was evaluated in vitro in PA rings exposed to cumulative concentrations of acetylcholine (ACh) and ADP. Structural abnormalities of PA were assessed morphometrically. PA of COPD patients developed lower maximal relaxation in response to ADP than both nonsmokers and smokers (P < 0.05 each) and a trend to reduced relaxation in response to ACh (P = 0.08). Maximal relaxation to ADP correlated with the degree of airflow obstruction (r = 0.48, P < 0. 01). Morphometrical analysis of PA revealed thicker intimas, especially in small arteries, in both smokers and COPD compared with nonsmokers (P < 0.05 each). We conclude that endothelial dysfunction of PA is already present in patients with mild COPD. In these patients, as well as in smokers with normal lung function, small arteries show thickened intimas, suggesting that tobacco consumption may play a critical role in the pathogenesis of pulmonary vascular abnormalities in COPD.

Bias Associated with Diet Samples in Audouin's Gulls

We analyzed five different types of food samples from Audouins Gull (Larus audouinii), collected during the breeding seasons of 1994 and 1995 at its two main breeding colonies, the Ebro Delta and the Chafarinas Islands. These food samples included spontaneous regurgitates, dry boli containing partially digested food, food remains, pellets, and prey identified during direct observations of chick provisioning. We compared estimates of biomass, levels of taxonomic determination allowed by each kind of food sample, and the associated potential biases to assess which sampling method provides the best estimate of diet in gulls. Regurgitates allowed identification of most prey to species level and reliable biomass estimates, but their collection was time-consuming and invasive. Dry boli provided almost the same information as regurgitates at order level and were easy to collect. However, both underestimated soft-bodied prey and prey with large, hard parts. Food remains provided an estimate of diet composition that was highly biased towards prey with large distinctive hard parts. However, food remains were a good complement to dry boli, enhancing biomass estimates for food items that had a good relationship of weight and linear measurements of prey..hard parts. Direct observation allowed identification of prey only to upper taxonomic categories, and is useful when only a broad categorization of prey types is required. Pellets showed important biases towards fish with robust otoliths, and inaccurate conversion to biomass, but they can be useful for monitoring variations in the consumption of certain prey items. Several factors such as time spent collecting, sample availability, disturbance to animals, and the status of the species studied need to be considered when deciding on a method of diet assessment sampling.

Diet of Yellow-legged Gull (Larus michahellis) chicks along the Spanish Western Mediterranean coast: the relevance of refuse dumps

In recent decades, the Yellow-legged Gull (Larus michahellis) has become a problematic species in many Mediterranean countries, mainly because it interferes with human interests. However, this gull also has a negative impact on several other bird species, many of which are classified as endangered. Two different European Union Action Plans are currently under development with the aim of decreasing the availability of food derived from human activities, such as garbage and fishery discards, which are considered to be the main causes of the superpopulations of this gull. Here, we describe the diet of Yellow-legged Gull chicks, with particular emphasis on establishing the dependence of each population on refuse dumps, in order to forecast changes in gull population dynamics in response to the management decisions being implemented. We sampled four colonies along the Western Mediterranean in Spain: the Medes Islands, the Ebro Delta, the Columbretes Islands, and Mazarrón Island. To elucidate their feeding ecology and to avoid obtaining a discrete estimation from a single sampling, we collected regurgitates from each colony three times throughout the chick-rearing period. Slightly differential feeding habits were observed between chick age classes. Younger chicks in all four colonies tended to be consistently provisioned with smaller prey such as invertebrates. Distinct uses of several foraging habitats among localities were observed. In particular, the use of refuse dumps was common and abundant in two of the colonies: the Medes and Mazarrón Islands. As a consequence of current management strategies, generalized reductions in Yellow-legged Gull populations and increases in the consumption of alternative food resources to those of fishery discards and refuse scraps are expected. Finally, we predict that decreased food availability will force some gulleries to increase predation on endangered species, thereby raising a conservation concern.

Trophic niche width and overlap of two sympatric gulls in the southwestern mediterranean

Abstract The diets of two potential competitor species, Audouins Larus audouinii and yellow-legged gulls Larus cachinnans, were examined while they bred at the Chafarinas Islands during 1993, 1994, and 1995. Data were collected during two commercial fishing regimes: (1) trawling and purse seine fisheries, and (2) diurnal trawlers only. Since the food supply for the gulls in this area was heavily reliant on the activity of purse seine fisheries, these contrasting situations allowed us to analyze short-term effects, induced by daily changes in food supply, on niche width, dietary shift, and niche overlap between the two species. Overall, both species relied mainly on fish for food, especially Clupeiforms, in the case of Audouins gull irrespective of the fishing situation, and in the case of the yellow-legged gull, only when purse seine fishing was in operation. When purse seine boats did not operate (food shortage), yellow-legged gulls broadened their niche, consuming equal amounts of all the feeding resources, and they showed a dietary shift toward a greater consumption of prey from refuse tips. In contrast, Audouins gulls did not change their niche width, but showed a slight dietary shift away from the consumption of epipelagic fish, compensated by an increase in reliance on benthic-mesopelagic resources. Niche overlap was clearly higher on days when both fishing fleets operated, probably because a superabundant food resource facilitates high overlap without affecting coexistence between the two species. Since our study was developed on the basis of daily variations in food supply, and competition effects are to be expected on a longer-term basis, these changes can be seen as the outcome of the coexistence of two species in stable competitive equilibrium.

Monitoring organochlorine pollution in Audouin's Gull eggs : the relevance of sampling procedures

Abstract Levels of PCBs, DDT and HCB were determined in 56 eggs belonging to 26 complete clutches of Audouins Gull (Larus audouinii) breeding in the Ebro Delta (Northeast Spain). DDT levels were comparable to those found in other areas of the region, while those of PCBs were far more variable being more site dependent. Variability in pollutant load was analysed for both intra- and inter-clutch effects. A case clutch approach was used to assess pollutant differences among clutch sizes and whether a laying order effect on egg xenobiotic contents exists. Two-egg clutches presented a significant female effect, whilst in three-egg clutches this was only significant for the second and third eggs. The environmental relevance of these results for monitoring programs and the usefulness of seabird eggs as biological indicators are discussed.

Influence of Refuse Sites on the Prevalence of Campylobacter spp. and Salmonella Serovars in Seagulls

ABSTRACT Wild animals are well-known reservoirs of Campylobacter and Salmonella. We investigated the influence of insalubrious diets on the prevalence of both enterobacteria in seagulls. Campylobacter occurrence in gull chicks sampled along the northeastern Iberian coast was directly related to the degree of refuse consumption. High Salmonella values from the sampling sites did not reflect any dietary relationship.

Predation on Common Tern Eggs in Relation to Sub-colony Size, Nest Aggregation and Breeding Synchrony

Abstract Avoidance of predators has long been regarded as a major benefit in colonial breeding. Nevertheless, field and comparative studies have not shown a clear relationship between predation and coloniality. In the present study, we examine the association between aerial egg predation on the Common Tern (Sterna hirundo), and sub-colony size, nest aggregation and reproductive synchrony. Fieldwork was carried out at the Ebro Delta colony (north-western Mediterranean), where Common Terns breed syntopically with potential predators. Sub-colonies placed in a small area were used instead of distant colonies in an attempt to minimize site effects, e.g., the abundance of predators. We used logistic regression with random effect (i.e., sub-colony) to test simultaneously the effect of the studied factors on the risk of predation. In addition, the random effect allowed us to account for the extra-binomial variability due to the potential non-independence of nests of the same sub-colony (clustered observations). Our results support the contention that both breeding in large colonies and in aggregated territories confers protection against aerial predators. In addition, synchrony in relation to the whole colony had no effect on the risk of egg predation. However, birds breeding asynchronously earlier in the season than the average in their own sub-colony were more likely to suffer egg predation than eggs from late asynchronous nesters.

Blood biomarkers and contaminant levels in feathers and eggs to assess environmental hazards in heron nestlings from impacted sites in Ebro basin (NE Spain).

Blood biomarkers and levels of major pollutants in eggs and feathers were used to determine pollution effects in nestlings of the Purple Heron Ardea purpurea and the Little Egret Egretta garzetta, sampled on three Ebro River (NE Spain) areas: a reference site, a site affected by the effluents of a chlor-alkali industry and the river Delta. The two impacted heron populations showed mutually different pollutant and response patterns, suggesting different sources of contamination. In the population nesting near the chlor-alkali plant, elevated levels of hexachlorobenzene (HCB) and polychlorobiphenyls (PCBs) in eggs, and mercury in feathers in A. purpurea chicks were related with reduced blood antioxidant defenses and increased levels of micronuclei. In Ebro Delta, high levels of plasmatic lactate dehydrogenase in A. purpurea chicks and high frequency of micronuclei in blood of both species were tentatively associated with intensive agricultural activities taking place in the area. These results provide the first evidence of a biological response in heron chicks to the release of pollutants at a chlor-alkali plant.

COMPARISON OF CONCORDANCE CORRELATION COEFFICIENT ESTIMATING APPROACHES WITH SKEWED DATA

The concordance correlation coefficient (CCC) is an index that assesses the agreement between continuous measures made by different observers. At least four methods are used to estimate the CCC: two (Lins method, Variance Components) which are defined on the basis that data are normally distributed, and the two others (U-statistics, GEE) which do not assume any particular distribution of the data. Here the four methods are compared with skewed data from a model in which the subject means follow a log-normal distribution while the within-subject variability is assumed to be normally distributed. An example of alcohol consumption is considered and a simulation study is performed.

Seabird feathers as monitors of the levels and persistence of heavy metal pollution after the Prestige oil spill

We measured heavy metal concentrations in yellow-legged gulls (n = 196) and European shags (n = 189) in order to assess the temporal pattern of contaminant exposure following the Prestige oil spill in November 2002. We analysed Pb, Cu, Zn, Cr, Ni and V levels in chick feathers sampled at four colonies during seven post-spill years (2003-2009), and compared results with pre-spill levels obtained from feathers of juvenile shag corpses (grown in spring/summer 2002). Following the Prestige wreck, Cu (4.3-10 μg g(-1)) and Pb concentrations (1.0-1.4 μg g(-1)) were, respectively, between two and five times higher than pre-spill levels (1.5-3.6 and 0.1-0.4 μg g(-1)), but returned to previous background concentrations after three years. Our study highlights the suitability of chick feathers of seabirds for assessing the impact of oil spills on heavy metal contamination, and provides the best evidence to date on the persistence of oil pollution after the Prestige incident.