Improvements in extremity dose assessment for ionising radiation medical applications

This study aims at testing the INTE ring dosemeter based on MCP-Ns and TLD-100 detectors on users from the field of medical applications, namely radiopharmacists, personnel at a cyclotron facility with corresponding FDG synthesis cells, interventional radiology technologists and radiologists. These users were chosen due to the fact that they have a significantly high risk of exposure to their hands. Following previous results, MCP-Ns TL thin material was used for radiology measurements, whereas TLD-100 was preferred for other applications. The dosemeters were tested to make sure that they were waterproof and that they could be sterilised properly prior to use. Results confirm the need to implement finger dosimetry, mainly for interventional radiologists as finger dose can be >50 times higher than whole-body dose and 3 times higher than wrist dose.

Infectious haemolytic anaemia causes jaundice outbreaks in seawater-cultured coho salmon, Oncorhynchus kisutch (Walbaum), in Chile

In the last 9 years, epizootics of an icterus condition has affected coho salmon, Oncorhynchus kisutch (Walbaum), reared in seawater cages in southern regions of Chile. At necropsy, fish from field cases exhibited signs of jaundice accompanied by pale light-brown livers and dark spleens. Histopathological and haematological results indicated that these fish presented haemolytic anaemia. After microbiological examination no bacterial or viral agents could be identified as aetiological agents of this disease. In an infectivity trial, coho salmon, Atlantic salmon, Salmo salar L., and rainbow trout, Oncorhynchus mykiss (Walbaum), were inoculated intraperitoneally with a filtrate of an organ homogenate (0.45 microm) from a diseased coho salmon and held for 60 days in tanks supplied with fresh water. The disease was only reproduced in coho salmon in which mortalities, beginning at day 23 post-inoculation (p.i.), reached a cumulative value of 24% at day 27 p.i. This condition was transmitted to non-inoculated cohabiting coho salmon suggesting that it is a waterborne disease. Thus, this icteric condition is caused by an infectious form of haemolytic anaemia, probably of viral aetiology, and coho salmon are more susceptible than either Atlantic salmon or rainbow trout.

Comparison of two extremity dosemeters based on LiF:Mg,Cu,P thin detectors for mixed beta-gamma fields

Two types of thin LiF:Mg,Cu,P detectors, GR-200F and MCP-Ns, have been characterised for use in the design of an extremity dosemeter for mixed beta-photon radiation fields. Both detectors consist of an extremely thin layer of sensitive material with effective thicknesses of 5 and 8 mg cm(-2), respectively, held in a 5 mg cm(-2) PVC ring holder. Dosimetric performance was analysed according to the ISO 12794 standard and compared with 240 mg cm(-2) TLD-100 measurements. In particular, the energy response was obtained for ISO narrow X-ray spectra, (137)Cs, (60)Co, (204)Tl and (90)Sr/(90)Y. From these measurements a mean calibration factor was calculated to estimate H(p)(0.07). Subsequently, the performance of the dosemeters was checked for a set of 10 different mixed photon and beta-photon fields. The study shows that the proposed dosemeters can estimate H(p)(0.07) in a wide range of mixed beta-photon fields with a maximum deviation from the given dose of 30% and an overall uncertainty of the order of 25% (k = 1). However, the results also highlight a large variability among the different thin detectors and, thus, the standard TLD-100 material is recommended whenever the workplace does not include low-energy beta radiation.

Anti-inflammatory activity of Lippia dulcis

Lippia dulcis hexane and ethanol extracts were tested for its anti-inflammatory activity in several animal models. Hexane extract showed to be inactive, but the ethanol extract at doses of 400 mg/kg produced significant inhibition of carrageenan-induced paw oedema and reduced the weight of cotton pellet-induced granuloma, moreover, the topical application of 0.5 mg/ear of this extract inhibited the edema induced with TPA by 49.13%, an effect which is of less intensity than that produced by indomethacine at the same dose.

Influence of the Saturation Chain and Head Group Charge of Phospholipids in the Interaction of Hepatitis G Virus Synthetic Peptides

Using the Langmuir technique, we have studied the properties at the air/water interface and the interaction of the hepatitis G virus synthetic peptide E1(53-66) and its palmitoyl derivative with membrane phospholipids. These phospholipids had different characteristics referring to the net charge and saturation of the acyl chain. The palmitoyl derivative was more stable at the air/water interface and in the kinetic at constant area measurements showed higher incorporation to the monolayer. The interaction was higher for saturated phospholipids and those with a negative net charge. When the peptides were in the subphase, they produced changes in the miscibility of mixed monolayers composed of DPPC/DPPG or DOPC/DOPG. It can be deduced from the results obtained that electrostatic interactions play a major role, but when the peptide is derivatized with the palmitoyl chain, hydrophobic interactions are added to the former ones. The interaction is also influenced by the saturation of the acyl chain.

Lipid disorders in antiretroviral-naive patients treated with lopinavir/ritonavir-based HAART: frequency, characterization and risk factors

OBJECTIVES

The aim of this study was to evaluate the frequency, characteristics and risk factors of lipid changes associated with lopinavir/ritonavir treatment in antiretroviral-naive patients.

METHODS

A prospective cohort of 107 antiretroviral-naive HIV-infected patients was followed for 12 months after starting lopinavir/ritonavir-based highly active antiretroviral therapy.

RESULTS

At 12 months, percentages of patients with hypercholesterolaemia and hypertriglyceridaemia were 17.4% and 40%, respectively. Mean increases in total cholesterol and triglycerides were 40.7 and 73.3 mg/dL. There was a significant increase in both low-density and high-density (HDL) cholesterol, and no increase in the total cholesterol/HDL ratio (from 4.16 at baseline to 4.49 after 12 months). Baseline cholesterol > 200 mg/dL and triglycerides > 150 mg/dL were independent risk factors for dyslipidaemia, while hepatitis C coinfection appeared to be protective.

CONCLUSIONS

Patients with elevated lipid values at baseline have the greatest risk of developing hypercholesterolaemia and hypertriglyceridaemia after starting lopinavir/ritonavir. Antiretroviral-naive patients coinfected with hepatitis C have a low risk of developing hyperlipidaemia after starting lopinavir/ritonavir.

Effects of the early administration of losartan on the functional and morphological aspects of postmyocardial infarction ventricular remodeling in rabbits

BACKGROUND

The effects of losartan (Los) on ventricular remodeling (VR) remain controversial. The objective was to determine whether early administration of Los to rabbits with myocardial infarction (MI) modifies VR.

METHODS

New Zealand rabbits underwent left coronary artery ligation. Four groups were analyzed: Sham (G(1); n = 13), MI (G(2); n = 13), Sham+Los (G(3); n = 13), and MI+Los (G(4); n = 13). Los (12.5 mg/kg/day) was administered from 3 h post-MI and during 35 days. At the end of the protocol, the hearts were isolated and perfused to determine pressure-volume curves (P/V). Hearts were weighed, cut, and stained with picrosirius red. The heart weight (HW)/body weight (BW) ratio was determined. Infarct size (IS;%), septum (SeT, mm) and scar thickness (ST, mm), myocyte area (microm(2)), and width (mum) were measured. RESULTS (X +/- S.E.M.): Los shifted the diastolic left ventricular (LV) P/V relationship to the right in sham and MI (P < .05 vs. sham), with no changes in the systolic relation. IS was G(2) = 25.38 +/- 5.31 and G(4) = 21.85 +/- 4.13 (NS); HW/BW was 0.34+/-0.01, 0.35 +/- 0.02, 0.29 +/- 0.02 (P < .05 vs. G(1) and G(2)), and 0.32 +/- 0.02 in G(1), G(2), G(3), and G(4), respectively. Scar collagen concentration (%) was lower in G(4) (P < .05 vs. G(2)). SeT was lower in G(3) and G(4) (P < .05 vs. G(2)). The width and area of the septum myocytes increased in the untreated infarct, and Los suppressed that increase.

CONCLUSION

The early administration of Los unfavorably modified post-MI VR, increasing ventricular dilation, reducing scar collagen concentration and thickness, and inhibiting myocytes width and area increase. The dilation observed in sham animals' hearts suggests that infarct was not the main factor in the dilation of the cavity.

[Pulmonary hemorrhage and anti-phospholipid syndrome]

The presence of anti-phospholipid antibodies (anticardiolipin antibodies and lupus anticoagulant) associated to venous and/or arterial thrombotic phenomena and fetal losses define the anti-phospholipid syndrome. On rare occasions severe hypoprothrombinemia associated with this disease as a cause of hemorrhagic manifestations has been described. In addition very few cases of alveolar hemorrhage in anti-phospolipid syndrome (APS) have been described, being this complication usually related to microthrombosis and/or capillaritis of pulmonary vessels. We describe two patients without previous clinical manifestations of anti-phospholipid syndrome that showed pulmonary hemorrhage with anticardiolipin antibodies positivity. The first of them, a 33-year-old male, began his disease with low prothrombin time and the presence of antiprothrombin antibodies. In the biopsy by thoracoscopy the presence of pulmonary hemorrhage without capillaritis nor thrombotic phenomena was demonstrated, becoming evident certain clinical improvement and normalization of the prothrombin time after receiving immunosuppressive treatment but with persistence of the pulmonary hemorrhage 5 years later. The second case, a 89-year-old male, began his condition with bilateral lung infiltrates and hemoptysis, anticardiolipin antibodies positivity, and thrombopenia, with recurrence of the condition 1 year later. After other etiological possibilities were ruled out, and despite hemorrhagic trait in both patients, we consider that they should be in the clinical context of the anti-phospholipid syndrome, although at this time they did not meet the criteria recognized in order to diagnose this disease. Within the ampliable clinical spectrum of the anti-phospholipid syndrome we should take into account the pulmonary hemorrhage.

[In vivo study of mitochondrial oxidation in obese patients treated by means of calorie restriction]

The energy restriction is the most common nutritional approach to treat obesity, whose efficiency depends on oxidative response against changes in body weight. In that context, the aim of the present work was to in vivo examine the mitochondrial oxidation of obese volunteers by the 2-keto[1-(13)C]isocaproate breath test, before and after weight loss. Thirty-two volunteers (men and women) participated: 16 controls (body mass index: 19.0-27.0 kg/m2), and 16 obese (body mass index: 30.0-41.6 kg/m2) who followed a caloric restriction program for 10 weeks (-500 kcal). Before and after dieting, the 2-keto[1-(13)C]isocaproate breath test was performed by ingestion of 1 mg/kg tracer and 20 mg/kg L-leucine, dissolved in 200 ml orange juice. Breath samples were recovered at baseline and at 10 min intervals for 2 h after ingestion. The 13C-enrichment in breath was measured by isotope ratio mass spectrometry and the percentage of mitochondrial oxidation of tracer (%13C) was calculated. The percentage of oxidized tracer marginally tended to be lower in obese than in controls (25.1 +/- 5.5%, vs 27.5 +/- 4.0%, p = 0.175). After the intervention, the mean of weight loss was -7.8% +/- 3% p < 0.001), and the mitocondrial oxidation of the tracer statistically increased (25.1 +/- 5.5% vs 34.3 +/- 5.2%, p < 0.001). In fact, the body weight and the percentage of oxidized 2-keto[1-(13)C]isocaproate were inversely related (r = -0.34, p = 0.018). Thus, the 2-keto[1-(13)C]isocaproate in vivo showed the mitochondrial adaptation of obese volunteers treated by caloric-restriction intake and provided new information about the weight loss process induced by an hypocaloric diet.

Brain death: Epidemiology and quality control of solid organ donor generation

Successful solid organ transplant programs need effective organ procurement systems. Evaluating and maintaining the quality of an organ procurement system requires multilevel institutional coordination as well as reliable information regarding potential donors. The objective of this study was to analyze the potential to generate adult solid organ donors at a countrywide level as well as at individual hospital levels in Uruguay from 2000 to 2002. The analyzed factors included: encephalic deaths (brain deaths) officially registered by the National Bank of Organs and Tissues (BNOT), the distribution of these individuals among the intensive care units (ICUs) located at various hospitals, the number of Real Donors at each hospital, and the relation between the brain deaths and the number of ICU beds equipped with artificial respirators. The Uruguayan solid organ donation rate is relatively high among Latin American Countries, but low in relation to developed countries. The conversion of potential donors to actual donors is similar to that seen in developed countries. However, the registered incidence of brain deaths in relation to the number of ICU beds is surprisingly below the recognized standard figure. To approach the reasons for this difference, efficient quality control mechanisms are needed in the various ICUs as well as comprehensive medical case history reviews of all patient records.

Mu opioid control of the N-methyl-D-aspartate-evoked release of [3H]-acetylcholine in the limbic territory of the rat striatum in vitro: diurnal variations and implication of a dopamine link

Using an in vitro microsuperfusion procedure, the release of newly synthesized [(3)H]-acetylcholine (ACh), evoked by N-methyl-D-aspartate (NMDA) receptor stimulation, was investigated in striosome-enriched areas and matrix of the rat striatum. The role of micro-opioid receptors, activated by endogenously released enkephalin, on the NMDA-evoked release of ACh was studied using the selective micro-opioid receptor antagonist, beta-funaltrexamine. Experiments were performed 2 (morning) or 8 (afternoon) h after light onset, in either the presence or absence (alpha-methyl-p-tyrosine, an inhibitor of dopamine synthesis) of dopaminergic transmission. As expected, based on the presence of micro-opioid receptors in striosomes, beta-funaltrexamine (0.1 nM, 10 nM and 1 microM) enhanced the NMDA (1 mM+10 microM D-serine)-evoked release of ACh in striosome-enriched areas but not in the matrix. Interestingly, these responses were significantly more pronounced in afternoon than in morning experiments. In the presence of alpha-methyl-p-tyrosine, the NMDA-evoked release of ACh was increased with similar amplitude in morning and afternoon experiments. However, in this condition (without dopamine transmission), the facilitatory effects of beta-funaltrexamine on the NMDA-evoked release of ACh were suppressed totally in the morning and only partially in the afternoon. The selective micro-opiate agonist, [D-Ala(2),N-Me-Phe(4),Gly(5)-ol]-enkephalin (1 microM, coapplied with NMDA), was without effect on the NMDA-evoked release of ACh but abolished both dopamine-dependent (morning) and dopamine-independent (afternoon) responses of beta-funaltrexamine (10 nM and 1 microM).Therefore, in the limbic territory of the striatum enriched in striosomes, the micro-opioid-inhibitory regulation of ACh release follows diurnal rhythms. While dopamine is required for this regulation in the morning and the afternoon, an additional dopamine-independent process is present only in the afternoon.

New evidence of red blood cell rheological disorders in beta-thalassaemia minor

Haemorheological parameters, such as red blood cell deformability, membrane elastic modulus and membrane surface viscosity in twenty one thalassaemia heterozygous patients (14 beta0/beta and 7 beta+/beta) were compared with normal individuals (n = 15). Parameters were measured applying a laser diffractometric method (ektacytometry). Thalassaemia erythrocytes showed statistically significant lower deformability and higher elastic modulus. Surface viscosity showed no significant differences in thalassaemia. Creep and recovery curves were registered by diffractometry. The normal recovery curve was fitted by a first order exponential decay function, expressing the fitting degree by the chi2 coefficient. The shape of the recovery curve in beta-thalassaemia patients (beta0/beta or beta+/beta) was significantly different from the control group. The possible mechanism of red blood cells abnormal rheological behaviour in beta-thalassaemia minor could be explained by a surface charge reduction. Our results enable us to conclude that the shape of the recovery curve (chi2 coefficient) could be considered as a marker that might be useful in beta-thalassaemia diagnosis.

[Strongyloides stercoralis in the south of Galicia]

Strongyloides stercoralis is the only parasite which can produce a chronic illness in humans, being through autoinfection. This nematode can also provoke death when patient's immunologic state deteriorates producing a massive hyper infection. The first patient with strongyloidiasis who has always lived in the Galician South area is described. The clinical picture consisted of unspecific cutaneous lesions and abdominal pain with severe peripheral eosinophilia (> 20,000/ml. The diagnosis was carried out observing the larvae in the fecal examination and was confirmed with a culture. Treatment with albendazole failed and the healing was reached with ivermectin. We must consider the possibility of strongyloidiasis because misdiagnosing these patients as eosinophilic gastroenteritis there would be a higher risk of hyperinfection if they are treated with corticosteroids.

Molecular basis of C(2+)-induced gelation in alginates and pectins: the egg-box model revisited

For many ionic polysaccharides, the ability to form gels in the presence of divalent cations such as calcium is the key to biological functions and technological applications. This is particularly true for alginates and pectins, where the regular occurrence of respectively alpha-L-(1-4)-guluronate residues and alpha-D-galacturonate residues generates ordered templates for polymer chain associations that are involved in physical gels. The molecular basis responsible for the strength and the stereospecificity of calcium interactions for the two polysaccharides were investigated in a previous paper (Braccini; et al. Carbohydr. Res. 1999, 119). In the present work, a novel molecular modeling procedure has been developed; it involves a pairing procedure that evaluates all the possible associations of the ordered polyuronate chains with calcium ions to form dimers. Starting from the stable ordered forms of polygalacturonate and polyguluronate, all possible ways to form Ca(2+)-bridged dimers were computed; the parallel and antiparallel relative arrangements of the chains were also considered. Despite the structural analogy between polyguluronate and polygalacturonate chains, significant differences at the level of chain-chain associations are found. The popular "egg box model" can still be referred to in the case of polyguluronate. However, it cannot be used to describe a pectate junction zone as the unique feature of two consecutive chelation site per repeat, that provides a favorable entropic contribution to the interchain association is not reproduced by this pioneering model. The body of these results corroborates the two-stage process in the mechanism of calcium gelation, where the formation of strongly linked dimer associations is followed by the formation of weak inter-dimer associations mainly governed by electrostatic interactions.

A complex plant cell wall polysaccharide: rhamnogalacturonan II. A structure in quest of a function

Walls of growing plants are extremely complex and sophisticated composite materials incorporating a dynamic assembly of polysaccharides, proteins and phenolics. Among the polysaccharides, the pectins encompass a group of acidic heteropolysaccharides; they offer a repertoire of structural complexity associated with the occurrence of, at least, three specific domains. Whereas most of these domains are notable for their structural heterogeneity, one of these, the so-called rhamnogalacturonan II (RG-II) exhibits a remarkable conservation throughout the plant kingdom. RG-II is thought to be the most complex plant polysaccharide on Earth (MW 5-10 kDa); its occurrence and strong conservation may indicate that it plays a major role in the structure and growth of higher plants. The present paper examines the most recent findings related to the occurrence, the structures, biosynthesis, biological role and properties, functional properties and technological applications of RG-II. Particular emphasis is given on the description of the three-dimensional structures of RG-II, in its monomeric and dimeric form as elucidated from the concerted investigations throughout 800 MHz NMR spectroscopy, light scattering, atomic force microscopy along with molecular mechanics and dynamics. Some attempts of deciphering of the structural role that RG-II may play in the cell wall of growing plants are presented.

Risk of serious skin disorders among users of oral antifungals: a population-based study

BACKGROUND

Serious skin disorders have been associated with the use of oral antifungals in a number of case reports and series of cases. However the incidence of these disorders remains unknown.

METHODS

We estimated the risk of serious skin disorders in a cohort of users of oral antifungals identified in the general population of the General Practice Research Database in the UK. The cohort included 61,858 patients, 20 to 79 years old, who had received at least one prescription for either oral fluconazole, griseofulvin, itraconazole, ketoconazole, or terbinafine.

RESULTS

The background rate of serious cutaneous adverse reactions (the one corresponding to non use of oral antifungals) was 3.9 per 10,000 person-years (95% CI 2.9-5.2). Incidence rates for current use were 15.4 per 10,000 person-years (1.9-55.7) for itraconazole, 11.1 (3.0-28.5) for terbinafine, 10.4 (1.3-37.5) for fluconazole, and 4.6 (0.1-25.8) for griseofulvin. Itraconazole was the antifungal associated with the highest relative risk, 3.9 (0.5-15.0), when compared to the risk among non users, followed by terbinafine and fluconazole, with relative risks of 2.8 (0.7-7.8) and 2.6 (0.3-10.1), respectively.

CONCLUSIONS

We conclude that cutaneous disorders associated with the use of oral antifungals in this study were all of mild severity and that the risk associated with the use of oral antifungals was slightly higher than the risk in non-users. The safety profile of terbinafine regarding cutaneous disorders is similar to other antifungals and in the very low range of risks associated with other drugs.

Cerebrospinal fluid and plasma concentrations of nitric oxide metabolites are increased in dementia with Lewy bodies

We compared cerebrospinal fluid (CSF) and plasma concentrations of nitric oxide metabolites (NO(-)(x)) in 22 patients with dementia with Lewy bodies (DLB) and 13 matched controls. We found a pronounced increase in NO(-)(x) CSF and plasma levels in DLB patients. No changes were found in L-arginine and L-citrulline levels in CSF or plasma. There was no correlation between CSF and plasma levels and age, age of onset, duration of the disease or scores of the MiniMental State Examination. These findings reveal that excessive nitric oxide production may be related to the pathogenesis of DLB.

Serum levels of coenzyme Q in patients with Lewy body disease

The purpose of the present study was to compare serum levels of coenzyme Q(10) (CoQ(10)) and the coenzyme Q(10) cholesterol (CoQ(10)/cholesterol) ratio in 18 patients with Lewy body disease (LBD) with 20 matched controls. The mean serum coenzyme Q10 levels in patients with LBD were significantly reduced with respect to control group, however, no differences were found in CoQ(10)/cholesterol ratio between LBD patients and control group. There was no correlation among CoQ(10) and CoQ(10)/cholesterol ratio with age, age of onset, body mass index, duration of the disease or scores of the Mini Mental State Examination, UPDRS and Hoehn and Yahr stage. These results suggest the involvement of this enzimatic system in the pathogenic mechanism of LBD.

New 3-[4-(3-substituted phenyl)piperazin-1-yl]-1-(benzo[b]thiophen-3-yl)propanol derivatives with dual action at 5-HT1A serotonin receptors and serotonin transporter as a new class of antidepressants

In this paper a series of new 3-[4-(3-substituted phenyl)piperazin-1-yl]-1-(benzo[b]thiophen-3-yl)propanol derivatives is presented as a new class of antidepressant drugs with dual activity at 5-HT1A serotonin receptors and serotonin transporter. The 5-HT1A receptor and 5-HT transporter binding affinities of hydroxylic compounds 4 a-e have been determined. The new compounds present nanomolar affinity for both activities, and 1-(benzo[b]thiophen-3-yl)-3-[4-(3-methoxyphenyl)piperazin-1-yl]propan-1-ol (4d) shows values (nM) of Ki = 86 for 5-HT1A receptors and Ki = 76 for the serotonin transporter, respectively.

New 3-[4-(aryl)piperazin-1-yl]-1-(benzo[b]thiophen-2-yl)propane derivatives with dual action at 5-HT1A serotonin receptors and serotonin transporter as a new class of antidepressants

Some benzo[b]thiophene derivatives with different substituents in positions 3 and 5 have been synthesized in order to obtain new dual antidepressant drugs. Compounds derived from 2-acetyl-3-methylbenzo[b]thiophene or 2-acetyl-3,5-dimethylbenzo[b]thiophene were prepared with two different phenylpiperazines (2-methoxy and 2-hydroxyphenylpiperazine) and evaluated for in vitro 5-HT1A receptor affinity and serotonin reuptake inhibition by radioligand assays. Compound 1-(3,5-dimethylbenzo[b]thiophen-2-yl)-3-[4-(2-methoxyphenyl)piperazin-1- yl]propan-1-ol (II.2.a) shows good values (nM) for both activities: Ki = 85 for 5-HT1A receptor and Ki = 120 for serotonin transporter.

Extremity and whole-body dosemeters for beta and beta gamma fields based on LiF:Mg,Cu,P thin detectors

This study aims at proposing two TL dosemeters: one for the whole body and another for the extremities, for beta and gamma fields. Selected sensible material consists of 5 mg x cm(-2) LiF:Mg,Cu,P film (GR-200F) manufactured in China. Calibration was carried out according to ISO 4037-3, in terms of Hp(0.07), and dosimetric performance was analysed on the basis of IEC-1066 and ISO-12794 Standards. Experiments showed a satisfactory sensitivity of the proposed dosemeters for detecting beta radiation at protection levels and a very good energy response; thus, highly recommending their use for weakly penetrating radiation measurements. However, the homogeneity and the reproducibility of GR-200F are not found to be as reliable as in standard materials.

Quantitative analysis of polycyclic aromatic hydrocarbons in sewage sludge from wastewater treatment plants

Polycyclic aromatic hydrocarbons (PAHs) are an important group of organic contaminants present in sewage sludge. Due to their persistence and toxic potential, information about their presence in sewage sludge is needed in order to assess applicability on agricultural land. A method for the gas chromatographic-mass spectrometric (GC-MS) determination was developed and applied to the trace determination of PAHs present in sewage sludge samples from six wastewater treatment plants (WWTPs) differing in the type of treatment and the origin of wastewater. PAHs were extracted from freeze-dried samples by a dichloromethane-methanol (2:1) mixture in a sonication bath. The sludge extracts were cleaned-up by an alumina column. The method showed recovery values varying from 60 to 98%. Four surrogate standards ([2H8]naphthalene, [2H10]anthracene, [2H12]benzo[a]anthracene, and [2H12]benzo[ghi]perylene) were used for quantitation by GC-MS. A reference sludge sample was analysed in order to validate the method. The sum of the 16 US Environmental Protection Agency PAHs analysed in the sewage sludge samples varied from 1.13 to 5.52 mg/kg. No significant difference between the different WWTPs was found.