RESUMO
Childhood-onset systemic lupus erythematosus (cSLE) is a chronic inflammatory multisystem autoimmune disease that requires multiple differential diagnoses. Munchausen by proxy syndrome (MBPS) is a form of child abuse, where a caregiver intentionally creates a medical history and induces or fabricates signs or disease in a patient. To our knowledge, there is no case report of MBPS mimicking cSLE diagnosis. We reported herein a 9-year-old male patient, with a history of multiple hospitalizations due to seizures with altered levels of consciousness. The mother reported malar rash, photosensitivity, alopecia, arthralgia, arterial hypertension, macroscopic hematuria, seizure and positive antinuclear antibodies. In the other service, he was treated with intravenous methylprednisolone, prednisone and mycophenolate mofetil. At 8 years and 8 months, he was admitted to our tertiary center with history of fever and macroscopic hematuria. Laboratory examinations were normal, including negative for antinuclear antibodies, anti-double stranded DNA, anticardiolipin, anti-Ro/SSA, anti-La/SSB, anti-RNP and anti-Sm antibodies. Multiple urine cultures revealed the presence of Enterococcus faecium, Acinetobacter sp., Stenotrophomonas maltophilia and Serratia marcescens, without any association with pyuria. At 8 years and 9 months, he was readmitted at emergency room with history of severe fever, headache, vomiting, photophobia, phonophobia and dizziness. The physical examination showed agitation, confusion, ataxic gait, slurred speech, horizontal nystagmus, painful facial expressions, tachycardia and weight loss. Brain magnetic resonance angiography and cerebrospinal fluid analysis were normal. During hospitalization, he had an acute episode of epistaxis and otalgia with excoriation in the auditory canal. At that moment, the suspicion of MBPS mimicking cSLE was raised and phenytoin intoxication was confirmed (peak phenytoin concentration was 45.4 mcg/mL, therapeutic range 10-20 mcg/mL). The mother and the patient were immediately separated, and she was replaced by another legal guardian. One week later, the neurological and other signs and symptoms were completely resolved. The child was placed under paternal custody with a court order and moved to another state. After that, the mother reported phenytoin use for her child and was referred to psychiatric follow-up. In conclusion, the first case of MBPS mimicking cSLE, resulting in multiple unnecessary examinations and treatments with delayed diagnosis was reported.
Assuntos
Síndrome de Munchausen Causada por Terceiro/diagnóstico , Idade de Início , Criança , Diagnóstico Tardio , Diagnóstico Diferencial , Humanos , Lúpus Eritematoso Sistêmico/diagnóstico , Masculino , Procedimentos DesnecessáriosRESUMO
OBJECTIVE: The purpose of the present review is an update on the diagnosis of prosthetic valve endocarditis (PVE), evaluating the additional value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) to the standard modified DUKE criteria on which for a long time is based the diagnostic strategy of the disease. MATERIALS AND METHODS: We did a comprehensive research on the studies reported in the literature and regarding the employment of 18F-FDG PET/CT in the early diagnosis of PVE in patients with suspected disease. Scientific databases have been examined such as Medline and PubMed, followed by a review of citations and reference lists. The research included the following terms: infective endocarditis, prosthetic heart valve and cardiac valve replacement infections, 18F-FDG PET/CT and endocarditis. RESULTS: The recent studies reported in the literature on the PVE diagnostic approaches showed elevated sensitivity and specificity values of 18F-FDG PET/CT ranging from 73 to 96.6% and from 80 to 94%, respectively, reducing the number of misdiagnosed patients. The usefulness of the radioisotopic procedure is even more important when the other diagnostic conventional diagnostic tools, such as echocardiography, are inconclusive or negative in patients in whom the diagnosis of PVE is definitively ascertained. However, false negative and positive results of 18F-FDG PET/CT were also ascertained in some studies interfering with image interpretation even if such limitation can be reduced with an adequate patient preparation, with a better knowledge of clinical course of the disease, of the treatment in progress and of the different technical aspects of the method. CONCLUSIONS: In different studies reported in the literature, 18F-FDG PET/CT proved to improve the diagnostic accuracy of the conventional modified DUKE criteria in patients with suspected IE, and in particular with PVE, giving the highest diagnostic performance and providing additional diagnostic benefits. Thus, the radioisotopic hybrid procedure should be included in the diagnostic protocol of PVE as complementary tool to modified DUKE criteria. Finally, the usefulness of 18F-FDG PET/CT in monitoring the response to antibiotic therapy, although the few data reported in the literature are encouraging, needs more numerous studies and with a major number of cases.
Assuntos
Endocardite Bacteriana/diagnóstico por imagem , Implante de Prótese de Valva Cardíaca , Próteses Valvulares Cardíacas , Valvas Cardíacas/diagnóstico por imagem , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada/métodos , Infecções Relacionadas à Prótese/diagnóstico por imagem , Diagnóstico Precoce , Endocardite Bacteriana/microbiologia , Fluordesoxiglucose F18/administração & dosagem , Valvas Cardíacas/cirurgia , Humanos , Infecções Relacionadas à Prótese/microbiologia , Sensibilidade e EspecificidadeRESUMO
Due to its peculiar geographical and morphological characteristics, Lake Como (Northern Italy) represents an interesting study-case for investigating the sub-basin scale circulation of persistent organic pollutants (POPs) that, despite being banned since the 1970s, have reached surprisingly high concentrations in some southern alpine lakes as a consequence of their release from melting glaciers in recent years. In particular, the Como Bay, which is located in the city of Como, seems noteworthy because its waters have a longer residence time than the other areas of the lake. The analyses of the historical concentration of PCBs, pp'DDT and its metabolites in a sediment core sampled from the Como Bay covering a time-period from their ban to recent times, showed that the DDTs have never experienced a significant (p < 0.05) decrease over time, with concentrations of the most abundant homologue, pp'DDE, ranging from 27 to 75 ng g(-1) d.w. Conversely PCBs significantly (p < 0.05) decreased towards recent times, reaching concentrations around 80 ng g(-1) d.w. The contribution of high altitude and local sources was recorded also in the food web: both zooplankton and the zooplanktivorous fish agone were mainly contaminated by pp'DDE (81.4 ng g(-1) w.w. and 534.6 ng g(-1) w.w. respectively) and by the PCB metabolite hexa-CB (449.7 ng g(-1) w.w. and 1672.1 ng g(-1) w.w. respectively). The DDT concentrations in the agone (sampled during the years 20062009) never exceeded the limits for human consumption in Italy, while concentrations of six selected PCBs exceeded human health advisory recommendations in one of the fish samples analysed, when it was approximately two times higher than the recommended value of 125 ng g(-1) w.w.
Assuntos
DDT/análise , Monitoramento Ambiental , Bifenilos Policlorados/análise , Poluentes Químicos da Água/análise , Animais , Organismos Aquáticos/metabolismo , Baías/química , Biota , DDT/metabolismo , Peixes/metabolismo , Cadeia Alimentar , Lagos/química , Bifenilos Policlorados/metabolismo , Poluentes Químicos da Água/metabolismo , Zooplâncton/metabolismoRESUMO
Inflammatory pseudotumour (IPT) is an uncommon disease with undefined pathogenesis. It is often characterized by local aggressiveness with compressive and displacing effects on surrounding structures. It may appear in different regions of the body, rarely involving perineural structures unilaterally. We present a case of a bilateral IPT around trigeminal branches in a patient with a long-term history of periorbital swelling and proptosis.
Assuntos
Exoftalmia/patologia , Granuloma de Células Plasmáticas/diagnóstico , Nervo Trigêmeo/patologia , Adulto , Diagnóstico Diferencial , Granuloma de Células Plasmáticas/patologia , Humanos , Imageamento por Ressonância Magnética , Masculino , Tomografia Computadorizada por Raios XRESUMO
Bivalve mussels are usually used for biomonitoring persistent toxic substances (PTS) in coastal ecosystems. Nevertheless, these organisms, which live attached on hard substrates, can be found along the sandy coasts only on human manufactured products. In this work different species collected in the Gulf of Gdansk were compared to evaluate their suitability for monitoring PTS pollution at a local scale. The clam Mya arenaria seems to represent an excellent indicator of sediment pollution, mainly for organotin compounds which are selectively bioaccumulated. Organochlorine compounds are bioaccumulated in the different species mainly in function of their lipid body burden. Habitat conditions (salinity, substrate, pollution), however, strongly limited the occurrence of different species in the sampling sites; the most ubiquitous species, the common shrimp Crangon crangon, resulted therefore the most suitable to be used for the comparison of PTS pollution in this aquatic environment. Although the blue mussel (Mytilus trossulus) was confirmed to be a very useful sentinel species to compare pollution level inside and outside the Gulf of Gdansk, we recommend the use of other species to give a more detailed picture of the pollution situation in coastal areas.
Assuntos
Ecossistema , Monitoramento Ambiental/métodos , Peixes , Invertebrados/efeitos dos fármacos , Água do Mar/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/toxicidade , Animais , Oceanos e Mares , Poluição da Água/análiseRESUMO
Androgenic and anti-androgenic compounds including p,p'-DDE, Diuron, Linuron, Fenarimol, Vinclozolin, 1-(3,4-dichlorophenyl) urea (DCPU), 1-(3,4-dichlorophenyl)-3-methylurea, (DCPMU), tributyltin (TBT) and triphenyltin (TPT) and their metabolites (DBT, MBT, DPT, MPT) as well as metallic elements (Ni, Cu, Zn, As, Cd, Pb, Co, Tl, Cr, Fe, Mn, Al, K, Mg, Na, Ca, Ba, Ti, Sn), PAHs (16 indicator compounds), DDTs and PCBs have been quantified in top layer (0-10 cm) of up to 37 surface sediment samples collected from several sites in costal zone of the Gulf of Gdansk, an inland freshwater area of Brdyujscie in Poland and the tidal flats of the Norderney Island, Wadden Sea in 2002-2003. These sites differed in the degree of anthropogenic activities, including chemical pollution and related impact on biota. Especially in sediments near shipyards, ship repair facilities, harbours, other industrial activities or close to municipal sewage treatment plant outlets butyltins, PAHs and some metallic elements were found at high concentrations. Diuron, Linuron and DCPMU were detected at a few sites, Fenarimol only once, while Vinclozolin and DCPU were not detected. DDT concentrations in the sediments from the Gdansk and Gdynia region of the Gulf show a stepwise decrease following the ban for production and use, while diffusion of PCBs at some industrial sites seems to continue. Elevated PAH concentrations in sediments seem to be mainly due to pyrogenic and less to mixed pyrogenic and petrogenic sources, while for a few sites rather petrogenic sources dominated. The reference sites in the Norderney Island, Wadden Sea showed similar or slightly higher loads of DDTs, BTs, PAHs, PCBs and metallic elements when compared to sediments from the least contaminated sites in the coastal Gulf of Gdansk area, while phenyltins were not detected at both spatially distant European areas.
Assuntos
Antagonistas de Androgênios/análise , Androgênios/análise , Sedimentos Geológicos/química , Poluição Química da Água/análise , Monitoramento Ambiental , Alemanha , Metais/análise , Compostos Orgânicos de Estanho/análise , Praguicidas/análise , Polônia , Bifenilos Policlorados/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Estações do AnoRESUMO
DDT homologues and PCBs were determined in eggs of two stationary species, great crested grebe (Podiceps cristatus) and mallard (Anas platyrhynchos), in three breeding areas of Lake Maggiore in 1998. As expected, much higher contamination levels of both DDTs and PCBs were found in the fish-eating great crested grebe than in the mallard. In many eggs these values exceeded the safety thresholds proposed for aquatic bird protection. However, no significant correlation could be found between the two classes of pollutants and shell thickness in great crested grebe eggs. While a DDT manufacturer was detected as the main source of DDT pollution in the Lake Maggiore environment, the reason for the surprisingly high PCB level remains unknown.
Assuntos
DDT/análise , Patos , Inseticidas/análise , Bifenilos Policlorados/análise , Poluentes Químicos da Água/análise , Animais , DDT/análogos & derivados , DDT/farmacocinética , Dieta , Ovos , Monitoramento Ambiental , Peixes , Cadeia Alimentar , Inseticidas/farmacocinética , Bifenilos Policlorados/farmacocinética , Distribuição Tecidual , Poluentes Químicos da Água/farmacocinéticaRESUMO
Nonylphenols (NPs) are the primary stable metabolites of alkylphenol polyethoxylates (APEs), a family of compounds widely used in industry and in some domestic products. As NPs accumulate in sediments in aquatic environments, the risk to benthic organisms needs to be assessed. In this study 4NP-spiked sediments were tested on larvae of the dipteran Chironomus riparius. First instar larvae obtained from populations at three different sources were used. To spike the sediments, an equilibration procedure between water and sediment was adopted to avoid the use of solvents. Lower 10-d LC50 values were determined for two populations of C. riparius from clean environments (315-465 and 315-350 microg g(-1) d.w., respectively) than those of a strain deriving from a population collected in a polluted river (600-680 microg g(-1) d.w.). Larval growth always decreased with increasing 4NP concentration but without any defined trend. The results of this study suggest that tolerance to the toxicant can be developed in populations of polluted environments and that testing procedures should be standardised.
Assuntos
Chironomidae , Fenóis/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Sedimentos Geológicos/química , Larva , Dose Letal Mediana , Fenóis/metabolismo , Testes de Toxicidade/normasRESUMO
A simple, rapid, and reliable reversed-phase high-performance liquid chromatographic method for the analysis of 16 amino acids of main interest in commercial fruit juices (pear, orange, grapefruit, pineapple, peach, and apricot) is described. No sample cleanup is required. The pH of the fruit juices is adjusted to alkaline value (8.5) using 200 mM borate buffer, then amino acid is converted to stable derivatives using 9-fluorenylmethyl-chloroformate. The excess of derivatization reagent is removed by a hydrophobic amine, 1-amino-adamantane hydrochloride. The derivatization procedure is simple, fast, and described in detail. Amino acids are detected at 263 nm and eluted within 35 min. The calibration, precision (< or = 6.1%), and recovery (102% +/- 4%) of the method are reported. The conditions of separation are optimized; however, serine partially overlapped with aspartic acid. The amino acid profile of fruit juices is consistent with data from the literature.
Assuntos
Aminoácidos/análise , Bebidas/análise , Cromatografia Líquida de Alta Pressão/métodos , Fluorenos/química , Frutas , Indicadores e Reagentes/química , Reprodutibilidade dos Testes , Espectrofotometria UltravioletaRESUMO
Zebra mussel (Dreissena polymorpha) is commonly used as contaminant bioindicator in Europe and North America. We used the zebra mussel to follow DDT pollution trends from 1996 to 1997 in Pallanza bay, Lake Maggiore, near the inlet of the River Toce, after a DDT-manufacturing plant discharging residues into a tributary of the River Toce had closed down. DDT contamination fell off sharply outside the bay, but tissue concentrations of the parent compound and residues remained high in molluscs sampled within the bay a year later. Molluscs collected in Pallanza bay in June 1997 released gametes earlier than those sampled at a nearby reference station. Histological studies showed that a significant percentage of these specimens showed marked oocyte degeneration suggesting that DDTs have endocrine-disrupting effects in this species.
Assuntos
Bivalves , DDT/efeitos adversos , Exposição Ambiental , Inseticidas/efeitos adversos , Reprodução/efeitos dos fármacos , Poluentes Químicos da Água/efeitos adversos , Animais , DDT/análise , Feminino , Inseticidas/análise , Itália , Masculino , Oócitos , Dinâmica Populacional , Estações do Ano , Distribuição Tecidual , Poluentes Químicos da Água/análiseRESUMO
The presence in wine of the fungal metabolite, ochratoxin A (OTA), represents a serious risk for consumer health. A variety of fining agents, including activated carbon, silica gel, potassium caseinate, egg albumin, and gelatin, was evaluated in relation to their abilities to remove OTA in fortified wines. Freundlich adsorption isotherms were used to model the adsorption behavior between ochratoxin A and the fining agent. Potassium caseinate and activated carbon were found to be the best fining agents that could be used to remove OTA in wine. Potassium caseinate removed up to 82% of OTA when used at 150 g/hL, whereas activated carbon showed the highest specific adsorption capacity due to a high surface area per mass and low adsorption of total polyphenols.
Assuntos
Carbono/química , Ocratoxinas/isolamento & purificação , Compostos de Potássio/química , Vinho/análise , Absorção , Sensibilidade e EspecificidadeRESUMO
Quantitative structure-activity relationships (QSAR) were performed on nine congenetic aromatic hydrocarbons. Acute response was evaluated in freshwater fish species. QSAR were built by Hansch's approaches and weighted holistic invariant molecular (WHIM) indices. The prediction power of QSAR from both approaches was evaluated. Single regression analysis derivated by Hansch's approach seem suitable for non-polar compounds. However, for all species, it has not a high predictive power (Q2(LOO)) of the biological activity from only K(ow) as molecular descriptor. Multiple regression analysis obtained from WHIM descriptors showed Q2(LOO) higher than 80%, indicating that molecular descriptors have a prediction power greater than K(ow).
Assuntos
Peixes , Hidrocarbonetos Aromáticos/toxicidade , Testes de Toxicidade/métodos , Animais , Modelos Teóricos , Peso Molecular , Medição de Risco , Relação Estrutura-AtividadeRESUMO
A high-performance liquid chromatographic method is proposed for the simultaneous separation of main carboxylic acids, carbohydrates, ethanol, glycerol, and 5-HMF in beer by direct injection. A column packed with a sulfonated divinyl benzene-styrene copolymer and an isocratic elution with 0.0045N sulfuric acid and acetonitrile (6%, v/v) are employed. UV and refractive index detectors connected in series are also used to reduce the matrix interference of phenolic compounds. In conditions described, nine compounds are quantitated in a single chromatographic run without any pretreatment except for sample dilution and filtration before injection. Precision, accuracy, linearity of response, limit of detection, and limit of quantitation are also evaluated for each compound. Satisfactory results are obtained to justify the application of this method to all phases of beer production for process and quality control.
Assuntos
Cerveja/análise , Carboidratos/análise , Ácidos Carboxílicos/análise , Cromatografia Líquida de Alta Pressão/métodos , Etanol/análise , Furaldeído/análogos & derivados , Furaldeído/análise , Glicerol/análise , Refratometria , Espectrofotometria UltravioletaRESUMO
Regenerative phenomena, which have the advantage of reproducing developmental processes in the adult organism, are very sensitive to environmental stress and represent stages that can be monitored for damage at the whole-organism, cellular and molecular levels. Some persistent and ubiquitous pollutants, which can affect the natural environment because of their bioaccumulation in organisms, exert their effects by acting as 'endocrine disrupters'. In this respect, they can cause dysfunction in steroid hormone production/metabolism and activity by their dramatic effects on gene expression, reproductive competence and growth. The aim of our present research was to assess the impact of such compounds on adult echinoderm reproductive physiology with particular reference to regeneration potential. It is known that vertebrate-type steroids are synthesized by echinoderms and play a role in the control of growth and reproduction. Our experimental model is the crinoid Antedon mediterranea, selected on the basis of its previously explored regenerative capabilities at the level of the arms. The regeneration response, analyzed at the tissue and cellular levels using both light and electron microscopy and immunocytochemistry, was employed to monitor the effects of exposure to persistent endocrine disrupter micropollutants such as polychlorinated biphenyls (PCBs) by means of laboratory tests performed under controlled conditions in terms of environmental variables and contamination levels. Our results indicate that exposure to endocrine disrupter compounds such as PCBs can induce anomalies in regeneration times, morphology and developmental mechanisms that can be interpreted in the light of significant dysfunctions in the endocrine mechanisms controlling regenerative development.
Assuntos
Equinodermos/fisiologia , Bifenilos Policlorados/farmacologia , Animais , Equinodermos/anatomia & histologia , Equinodermos/efeitos dos fármacos , Glândulas Endócrinas/efeitos dos fármacos , Extremidades/fisiologia , Bifenilos Policlorados/metabolismo , Regeneração/efeitos dos fármacosRESUMO
Several toxicity-based procedures have been proposed for waste water risk assessment but the toxic agents could never be identified in these very complex mixtures. A procedure was adopted using disposable solid-phase extraction cartridges to extract organic chemicals and preparative HPLC to fractionate them in relation of their hydrophobicity. Acute toxicity of whole samples and their fractions was measured on Daphnia magna, using a commercially available biokit. The procedure was applied to leachate from an industrial landfill and a textile effluent. In both cases the toxic effects due to xenobiotics were highest in the most hydrophobic HPLC fraction. The compounds responsible for the observed toxicity were identified and quantified by GC-MS. Reconstructed mixtures were analysed to assess their fitting with GC profiles and tested for toxicity to compare the responses of individual chemicals and mixtures.
Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Poluentes Químicos da Água/toxicidade , Água/análise , Animais , Daphnia/efeitos dos fármacos , Esgotos/análise , Indústria Têxtil , Poluentes Químicos da Água/análiseRESUMO
Three immunoaffinity clean-up procedures to analyse ochratoxin A (OTA) in wines were compared. The direct wine clean-up with Ochraprep and OchraTest columns gave equivalent results in terms of recovery and precision if compared with the reference procedure involving a preliminary extraction of OTA with chloroform. OTA quantification limit in wine ranged from 0.020 to 0.045 microg/l. The 'on-flow' OTA emission spectrum (excitation 333 nm) showed a maximum at 460 nm and could be used to confirm the quantitative results. The analysis of 11 red and white wines gave no significant quantitative differences between the three clean-up techniques.
Assuntos
Cromatografia de Afinidade/métodos , Cromatografia Líquida de Alta Pressão/métodos , Micotoxinas/análise , Ocratoxinas/análise , Vinho/análise , Sensibilidade e EspecificidadeRESUMO
The EC official method of total SO2 analysis in grape juice was modified in 1990. The main improvements concerned the amount and concentration of H3PO4 used during the distillation to recover the combined SO2 and the standardization of the distillation time at 15 min. This comparative study evaluated the total SO2 level of 12 grape juices determined by five methods, including distillation, iodimetric and enzymatic-based methods. Attention was focused on the total SO2 legal limit of 10 mg/l fixed in Europe for grape juice. Analysis of variance disclosed a significant difference among the total SO2 content in grape juices determined by five methods. Each analytical method showed limits in relation of their ability to release the combined SO2. In particular, the SO2 bonded to phenolic compounds is partially released at low pH in the acidified juice leading to higher results.
Assuntos
Bebidas/análise , Rosales/química , Dióxido de Enxofre/análise , Análise de Variância , Concentração Máxima Permitida , Extratos Vegetais/químicaRESUMO
ABSTRACT Phloretin glycosides are bioactive compounds naturally present in apple fruits. The highest amount of phloretin glycosides was significantly found in apple pureées and commercial juices as a consequence of the processing conditions.
RESUMO
Polychlorinated biphenyl (PCB) and chlorinaed pesticide levels in eggs of two terrestrial (kestrel and sparrowhawk) and two aquatic (heron and mallard) birds were determined in inhabited areas and woodlands of Calabria. The eggs of the two terrestrial raptors were more polluted than those of the aquatic birds. Among the raptors, the kestrel demonstrated the highest level of pollution because it lives close to villages, whereas sparrowhawk lives in forests. The highest PCB and DDT residue concentrations found in kestrel (11.3 and 8.7 mg g-1 lipid, respectively) could cause shell thinning. Aquatic species show a higher DDT/DDE ratio than terrestrial species, probably because DDT is degraded more slowly in aquatic environments. However, point DDT sources seem to be present in this region.
Assuntos
Poluentes Ambientais/toxicidade , Inseticidas/toxicidade , Óvulo/efeitos dos fármacos , Óvulo/metabolismo , Bifenilos Policlorados/toxicidade , Animais , Aves , DDT/farmacocinética , DDT/toxicidade , Diclorodifenil Dicloroetileno/farmacocinética , Diclorodifenil Dicloroetileno/toxicidade , Poluentes Ambientais/farmacocinética , Cadeia Alimentar , Inseticidas/farmacocinética , Itália , Metabolismo dos Lipídeos , Bifenilos Policlorados/farmacocinética , Especificidade da EspécieRESUMO
Polychlorinated biphenyls (PCBs) and chlorinated pesticides were determined in several organisms and in the sediment sampled in the final stretch of the River Po (Italy). Bioconcentration models were used in order to test the equilibrium condition between biotic and abiotic compartments. The oligochaetes-sediment model fitted very well with the experimental results. The only exception was hexachlorobenzene. The results regarding the fish species demonstrate that most PCB congeners and p,p'-DDE are biomagnificated in the River Po ecosystem but to a lesser extent than expected on the basis of a four-step food chain model. In particular, most species approached to the third trophic level, while Perca fluviatilis concentrations correspond to a higher level but accumulate less than predicted by the model for a top predator.