21 resultados para Prenatal Exposure Delayed Effects

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Life of children exposed to alcohol or drugs in utero This study focused on the growth environment, physical development and socio-emotional development of children, aged 16 and under, who had been exposed to alcohol (n=78) or drugs (n=15) in utero. The aim of the study was to obtain a comprehensive picture of the living conditions of these children and to examine the role of the growth environment in their development. The study was carried out using questionnaires, written life stories and interviews. Attachment theory was used as a background theory in the study. Over half of the children exposed to alcohol were diagnosed with foetal alcohol syndrome (FAS), one quarter was diagnosed with foetal alcohol effects (FAE), and one fifth had no diagnosis. Most of the children exposed to drugs had been exposed to either amphetamines or cannabis, and a smaller number to heroin. Some of the children exposed to alcohol were mentally handicapped or intellectually impaired. The children exposed to drugs did not exhibit any serious learning difficulties but a considerable number of them had socio-emotional development problems. Language and speech problems and attention, concentration and social interaction problems were typical among both the children exposed to alcohol and those exposed to drugs. Only one child had been placed into long-term foster care in a family immediately after leaving the maternity hospital. In biological families there had been neglect, violence, mental health problems, crime and unemployment, and many parents were already dead. Two of the children had been sexually abused and four were suspected of having been abused. From the point of view of the children's development, the three most critical issues were 1) the range of illnesses and handicaps that had impaired their functional capacity as a result of their prenatal exposure to alcohol, 2) child's age at the time of placement on a long-term basis, and 3) the number of their traumatic experiences. The relationship with their biological parents after placement also played a role. Children with symptoms were found in all diagnosis categories and types of exposure. Children with the smallest number of symptoms were found among those who had never lived with their biological parents. Almost all children were exhibiting strong symptoms at the time of placement in foster care. In most cases, they were behaving in a disorderly manner towards others, but some children were withdrawn. The most conspicuous feature among those with the most severe symptoms was their disorganized behaviour. Placement in a foster family enhanced the children's development, but did not solve the problems. The foster parents who brought these children up did not receive as much therapy for the children and support for the upbringing as they appear to have needed. In Finland, transfer to long-term custody is based on strict criteria. The rights of children prescribed in the child protection law are not fulfilled in practice. Key words: FASD, FAS, FAE, alcohol exposure, drugs exposure, illegal drugs, early interaction, child development, attachment

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The goal of this thesis was to examine the ecophysiological responses of Scots pine (Pinus sylvestris L.), with an emphasis on the oxidative enzyme peroxidase and plant phenolics to environmental stresses like elevated levels of nickel (Ni) and copper (Cu), and herbivory. The effects of Ni and Cu were studied in a gradient survey at a sulphur dioxide contaminated site in the Kola Peninsula, and with experiments in which seedlings were exposed to Ni mist or to Ni and Cu amended into the soil. In addition, experimental Ni exposure was combined with disturbance of the natural lichen cover of the forest ground layer. Pine sawfly attack was simulated in the early season defoliation experiment, in which mature Scots pine were defoliated (100 %) during two successive years in a dry, nutrient-poor Scots pine stand. In addition, the effect of previous defoliation on the growth of sawfly (Diprion pini L.) larvae was studied. Apoplastic peroxidase activity was elevated in the needles of pine in a Ni- , Cu- and SO2- polluted environment, which indicated an increased oxidative stress. Increased foliar peroxidase activity due to Ni contamination was shown in the experiment, in which Ni was added as mist. No such response was found in peroxidase acitivity of the roots exposed to elevated Ni and/or Cu in the soil. Elevated Ni in the soil increased the concentration of foliar condensed tannins, which are able to bind heavy metals in the cells. Addition of low levels of Ni in the soil appeared to benefit pine seedlings, which was seen as promoted shoot growth and better condition of the roots. Wet Ni deposition of 2000 mg m-2 reduced growth and survival of pine seedlings, whereas deposition levels 200 mg m-2 or 20 mg m-2 caused no effects in a 2-y lasting experiment. The lichen mat on the forest floor did not act as an effective buffer against the adverse impacts of heavy metals on pine seedlings. However, some evidence was found indicating that soil microbes profited from the lichen mat. Artificial defoliation increased peroxidase activity in the Scots pine needles. In addition, defoliation decreased nitrogen, diamine putrescine and glucose concentrations in the needles and increased the concentrations of several phenolic compounds, starch and sucrose. Previous artificial defoliation led to poor growth of sawfly larvae reared on the pines, suggesting delayed induced resistance in Scots pine. However, there was no consistent relationship between inducibility (proportional increase in a compound following defoliation) and adverse effects on the growth of pine sawfly larvae. The observed inducible responses in needle phenolics due to previous defoliation thus appear to represent non-specific responses against sawflies.

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Activation of midbrain dopamine systems is thought to be critically involved in the addictive properties of abused substances. Drugs of abuse increase dopamine release in the nucleus accumbens and dorsal striatum, which are the target areas of mesolimbic and nigrostriatal dopamine pathways, respectively. Dopamine release in the nucleus accumbens is thought to mediate the attribution of incentive salience to rewards, and dorsal striatal dopamine release is involved in habit formation. In addition, changes in the function of prefrontal cortex (PFC), the target area of mesocortical dopamine pathway, may skew information processing and memory formation such that the addict pays an abnormal amount of attention to drug-related cues. In this study, we wanted to explore how long-term forced oral nicotine exposure or the lack of catechol-O-methyltransferase (COMT), one of the dopamine metabolizing enzymes, would affect the functioning of these pathways. We also wanted to find out how the forced nicotine exposure or the lack of COMT would affect the consumption of nicotine, alcohol, or cocaine. First, we studied the effect of forced chronic nicotine exposure on the sensitivity of dopamine D2-like autoreceptors in microdialysis and locomotor activity experiments. We found that the sensitivity of these receptors was unchanged after forced oral nicotine exposure, although an increase in the sensitivity was observed in mice treated with intermittent nicotine injections twice daily for 10 days. Thus, the effect of nicotine treatment on dopamine autoreceptor sensitivity depends on the route, frequency, and time course of drug administration. Second, we investigated whether the forced oral nicotine exposure would affect the reinforcing properties of nicotine injections. The chronic nicotine exposure did not significantly affect the development of conditioned place preference to nicotine. In the intravenous self-administration paradigm, however, the nicotine-exposed animals self-administered nicotine at a lower unit dose than the control animals, indicating that their sensitivity to the reinforcing effects of nicotine was enhanced. Next, we wanted to study whether the Comt gene knock-out animals would be a suitable model to study alcohol and cocaine consumption or addiction. Although previous work had shown male Comt knock-out mice to be less sensitive to the locomotor-activating effects of cocaine, the present study found that the lack of COMT did not affect the consumption of cocaine solutions or the development of cocaine-induced place preference. However, the present work did find that male Comt knock-out mice, but not female knock-out mice, consumed ethanol more avidly than their wild-type littermates. This finding suggests that COMT may be one of the factors, albeit not a primary one, contributing to the risk of alcoholism. Last, we explored the effect of COMT deficiency on dorsal striatal, accumbal, and prefrontal cortical dopamine metabolism under no-net-flux conditions and under levodopa load in freely-moving mice. The lack of COMT did not affect the extracellular dopamine concentrations under baseline conditions in any of the brain areas studied. In the prefrontal cortex, the dopamine levels remained high for a prolonged time after levodopa treatment in male, but not female, Comt knock-out mice. COMT deficiency induced accumulation of 3,4-dihydroxyphenylacetic acid, which increased further under levodopa load. Homovanillic acid was not detectable in Comt knock-out animals either under baseline conditions or after levodopa treatment. Taken together, the present results show that although forced chronic oral nicotine exposure affects the reinforcing properties of self-administered nicotine, it is not an addiction model itself. COMT seems to play a minor role in dopamine metabolism and in the development of addiction under baseline conditions, indicating that dopamine function in the brain is well-protected from perturbation. However, the role of COMT becomes more important when the dopaminergic system is challenged, such as by pharmacological manipulation.

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Nicotine, the addictive compound of tobacco products, exerts its effects in the brain by binding to neuronal acetylcholine nicotinic receptors (nAChRs). The aim of the present study was to increase the knowledge of nicotine s complex effects, the focus being on homomeric alpha7-nAChRs that are widely expressed in the brain. Nicotinic regulation of differential signalling molecules including transcriptional regulators was also studied. We found that the number of alpha7-nAChRs is increased in specific brain regions in mice, in a time-dependent manner after chronic oral nicotine administration. Our results suggest that in addition to alpha4beta2-nAChRs, the other major nAChR subtype expressed in the brain, the number of alpha7-nAChRs is affected by chronic presence of nicotine. We suggest that when studying the long-term effects of nicotine, the duration on administration is of great importance. Next, we observed that nicotine exposure induces accumulation of cAMP in cell cultures expressing nAChRs. Furthermore, nicotine-induced alpha7-nAChR upregulation was potentiated by treatments enhancing cAMP-signalling, suggesting a role for cAMP in the upregulation process. Protein kinase C (PKC) was found essential for the basal regulation of alpha7-nAChR number. The nicotine-evoked alpha7-nAChR upregulation could be further increased by PKC overexpression. Thirdly, the effects of nicotine on dopamine and cAMP regulated phosphoprotein (DARPP-32) were characterised in rat brain. The results show that DARPP-32 is regulated by both acute and long-term nicotine treatment in the striatal subdivisions. The effect of acute nicotine is dose-dependent and the three striatal regions display differential sensitivities to nicotine. Chronic nicotine is also able to regulate DARPP-32 signalling with prominent effect seen in the nucleus accumbens (NAc), suggesting a role for DARPP-32 in the mediation of long-term effects of nicotine. Finally, the regulation of transcription factors Elk-1 and FosB/deltaFosB by nicotine was investigated. We found that Elk-1 is activated by acute nicotine selectively in the NAc core and hippocampal area CA1, whereas acute nicotine does not affect FosB/deltaFosB. Long-term intermittent or continuous nicotine increases the level of total Elk-1 in the same brain regions as acute nicotine. FosB/deltaFosB is also affected by chronic nicotine. Thus, similarly to other drugs of abuse, nicotine regulates transcriptional regulators Elk-1 and FosB/deltaFosB. These results bring further support for a common mechanism underlying the development of addiction. Nicotine s positive effects on learning and memory might involve the transcription factor Elk-1 based on the changes seen in the hippocampus, the key area in cognitive functions.

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Fumonisin B1 (FB1) is a mycotoxin produced by the fungus Fusarium verticillioides, which commonly infects corn and other agricultural products. Fusarium species can also be found in moisture-damaged buildings, and therefore there may also be human exposure to Fusarium mycotoxins, including FB1. FB1 affects the metabolism of sphingolipids by inhibiting the enzyme ceramide synthase. It is neuro-, hepato- and nephrotoxic, and it is classified as possibly carcinogenic to humans. This study aimed to clarify the mechanisms behind FB1-induced neuro- and immunotoxicity. Four neural and glial cell lines of human, rat and mouse origin were exposed to graded doses of FB1 and the effects on the production of reactive oxygen species, lipid peroxidation, intracellular glutathione levels, cell viability and apoptosis were investigated. Furthermore, the effects of FB1, alone or together with lipopolysaccharide (LPS), on the mRNA and protein expression levels of different cytokines and chemokines were studied in human dendritic cells (DC). FB1 induced oxidative stress and cell death in all cell lines studied. Generally, the effects were only seen after prolonged exposure at 10 and 100 µM of FB1. Signs of apoptosis were also seen in all four cell lines. The sensitivities of the cell lines used in this study towards FB1 may be classified as human U-118MG glioblastoma > mouse GT1-7 hypothalamic > rat C6 glioblastoma > human SH-SY5Y neuroblastoma cells. When comparing cell lines of human origin, it can be concluded that glial cells seem to be more sensitive towards FB1 toxicity than those of neural origin. After exposure to FB1, significantly increased levels of the cytokine interferon-γ (IFNγ) were detected in human DC. This observation was further confirmed by FB1-induced levels of the chemokine CXCL9, which is known to be regulated by IFNγ. During co-exposure of DC to both LPS and FB1, significant inhibitions of the LPS-induced levels of the pro-inflammatory cytokines interleukin-6 (IL-6) and IL-1β, and their regulatory chemokines CCL3 and CCL5 were observed. FB1 can thus affect immune responses in DC, and therefore, it is rather likely that it also affects other types of cells participating in the immune defence system. When evaluating the toxicity potential of FB1, it is important to consider the effects on different cell types and cell-cell interactions. The results of this study represent new information, especially about the mechanisms behind FB1-induced oxidative stress, apoptosis and immunotoxicity, as well as the varying sensitivities of different cell types towards FB1.

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Objectives. School personnel who are exposed to school violence are at risk in developing post traumatic stress disorder (PTSD). In Finland there have been two such events in recent years, Jokela school shooting on 7.11.2007 and Kauhajoki school shooting about a year later. The aim of the present study was to examine the presence and change in PTSD symptoms during the first year after the Jokela school shooting. A second aim was to study how the initial exposure and treatment affects the symptom levels of PTSD. There were four hypotheses: 1) The PTSD symptoms are higher for the people who were exposed to the school shooting than for the people who did not face the stressor. 2) The PTSD symptoms increase in the follow up for the people at the school which was not attacked because of the second incident brought up the memories from the Jokela school shooting. 3) Those who have greater exposure to the shooting will have higher level of PTSD symptoms at both 4 and 11 months after the shooting than those who were not directly exposed to the shooting. 4) The PTSD symptoms are reduced more in the group that starts treatment right after the traumatic event than in other groups. Methods. A sample of 24 members of Jokela school personnel were examined four months after the incident and 16 were reassessed 11 month after the incident. To study the change and level of symptoms in other schools during the same period, a group with no exposure to the shooting was used as a control group (n=22). The assessment included Post Traumatic Stress Disorder Checklist Specific (PCL-S) and a social and professional support questionnaire. In addition questions about timing of support and experiences of psychological debriefing were asked. Results and conclusions. Most participants in the study group experienced some symptoms of PTSD at both 4 and 11 months. In both measures three participants from the study group fulfilled the diagnostic criteria for PTSD. The study group and control group differed significantly in overall symptom levels. The study group had more PTSD symptoms in the first measure but in the follow-up the study group’s PTSD symptoms decreased and the control group’s increased. There was a significant change in the study groups PTSD symptom level for those who started treatment right after the traumatic event. The results from this study showed that an exposure to school shooting has long-term effects on school personnel. The findings suggest that it is crucial to plan a comprehensive and long-term treatment for school personnel in the aftermath of school shooting.

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Catechol-O-methyltransferase (COMT) metabolizes catecholamines such as dopamine (DA), noradrenaline (NA) and adrenaline, which are vital neurotransmitters and hormones that play important roles in the regulation of physiological processes. COMT enzyme has a functional Val158Met polymorphism in humans, which affects the subjects COMT activity. Increasing evidence suggests that this functional polymorphism may play a role in the etiology of various diseases from schizophrenia to cancers. The aim of this project was to provide novel biochemical information on the physiological and especially pathophysiological roles of COMT enzyme as well as the effects of COMT inhibition in the brain and in the cardiovascular and renal system. To assess the roles of COMT and COMT inhibition in pathophysiology, we used four different study designs. The possible beneficial effects of COMT inhibition were studied in double-transgenic rats (dTGRs) harbouring human angiotensinogen and renin genes. Due to angiotensin II (Ang II) overexpression, these animals exhibit severe hypetension, cardiovascular and renal end-organ damage and mortality of approximately 25-40% at the age of 7-weeks. The dTGRs and their Sprague-Dawley controls tissue samples were assessed with light microscopy, immunohistochemistry, reverse transcriptase-polymerase chain reaction (RT-PCR) and high-pressure liquid chromatography (HPLC) to evaluate the tissue damages and the possible protective effects pharmacological intervention with COMT inhibitors. In a second study, the consequence of genetic and pharmacological COMT blockade in blood pressure regulation during normal and high-sodium was elucidated using COMT-deficient mice. The blood pressure and the heart rate were measured using direct radiotelemetric blood pressure surveillance. In a third study, the effects of acute and subchronic COMT inhibition during combined levodopa (L-DOPA) + dopa decarboxylase inhibitor treatment in homocysteine formation was evaluated. Finally, we assessed the COMT enzyme expression, activity and cellular localization in the CNS during inflammation-induced neurodegeneration using Western blotting, HPLC and various enzymatic assays. The effects of pharmacological COMT inhibition on neurodegeneration were also studied. The COMT inhibitor entacapone protected against the Ang II-induced perivascular inflammation, renal damage and cardiovascular mortality in dTGRs. COMT inhibitors reduced the albuminuria by 85% and prevented the cardiovascular mortality completely. Entacapone treatment was shown to ameliorate oxidative stress and inflammation. Furthermore, we established that the genetic and pharmacological COMT enzyme blockade protects against the blood pressure-elevating effects of high sodium intake in mice. These effects were mediated via enhanced renal dopaminergic tone and suggest an important role of COMT enzyme, especially in salt-sensitive hypertension. Entacapone also ameliorated the L-DOPA-induced hyperhomocysteinemia in rats. This is important, since decreased homocysteine levels may decrease the risk of cardiovascular diseases in Parkinson´s disease (PD) patients using L-DOPA. The Lipopolysaccharide (LPS)-induced inflammation and subsequent delayed dopaminergic neurodegeneration were accompanied by up-regulation of COMT expression and activity in microglial cells as well as in perivascular cells. Interestingly, similar perivascular up-regulation of COMT expression in inflamed renal tissue was previously noted in dTGRs. These results suggest that inflammation reactions may up-regulate COMT expression. Furthermore, this increased glial and perivascular COMT activity in the central nervous system (CNS) may decrease the bioavailability of L-DOPA and be related to the motor fluctuation noted during L-DOPA therapy in PD patients.

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The aim of this thesis was to increase our knowledge about the effects of seed origin on the timing of height growth cessation and field performance of silver birch from different latitudes, with special attention paid to the browsing damage by moose in young birch plantations. The effect of seed origin latitude and sowing time on timing of height growth cessation of first-year seedlings was studied in a greenhouse experiment with seven seed origins (lat. 58º - 67ºN). Variation in critical night length (CNL) for 50 % bud set within two latitudinally distant stands (60º and 67ºN) was studied in three phytotron experiments. Browsing by moose on 5-11 -year-old silver birch saplings from latitudinally different seed origins (53º - 67ºN) was studied in a field experiment in southern Finland. Yield and stem quality of 22-year-old silver birch trees of Baltic, Finnish and Russian origin (54º - 63ºN) and the effect of latitudinal seed transfers were studied in two provenance trials at Tuusula, southern and Viitasaari, central Finland. The timing of height growth cessation depended systematically on latitude of seed origin and sowing date. The more northern the seed origin, the earlier the growth cessation and the shorter the growth period. Later sowing dates delayed growth cessation but also shortened the growth period. The mean CNL of the southern ecotype was longer, 6.3 ± 0.2 h (95 % confidence interval), than that of the northern ecotype, 3.1 ± 0.3 h. Within-ecotype variance of the CNL was higher in the northern ecotype (0.484 h2) than in the southern ecotype (0.150 h2). Browsing by moose decreased with increasing latitude of seed origin and sapling height. Origins transferred from more southern latitudes were more heavily browsed than the more northern native ones. Southern Finnish seed origins produced the highest volume per unit area in central Finland (lat. 63º11'N). Estonian and north Latvian stand seed origins, and the southern Finnish plus tree origins, were the most productive ones in southern Finland (lat. 60º21'N). Latitudinal seed transfer distance had a significant effect on survival, stem volume/ha and proportion of trees with a stem defect. The relationship of both survival and stem volume/ha to the latitudinal seed transfer distance was curvilinear. Volume was increased by transferring seed from ca. 2 degrees of latitude from the south. A longer transfer from the south, and transfer from the north, decreased the yield. The proportion of trees with a stem defect increased linearly in relation to the latitudinal seed transfer distance from the south.

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We report here the structures and properties of heat-stable, non-protein, and mammalian cell-toxic compounds produced by spore-forming bacilli isolated from indoor air of buildings and from food. Little information is available on the effects and occurrence of heat-stable non-protein toxins produced by bacilli in moisture-damaged buildings. Bacilli emit spores that move in the air and can serve as the carriers of toxins, in a manner similar to that of the spores of toxic fungi found in contaminated indoor air. Bacillus spores in food cause problems because they tolerate the temperatures applied in food manufacture and the spores later initiate growth when food storage conditions are more favorable. Detection of the toxic compounds in Bacillus is based on using the change in mobility of boar spermatozoa as an indicator of toxic exposure. GC, LC, MS, and nuclear magnetic resonance NMR spectroscopy were used for purification, detection, quantitation, and analysis of the properties and structures of the compounds. Toxicity and the mechanisms of toxicity of the compounds were studied using boar spermatozoa, feline lung cells, human neural cells, and mitochondria isolated from rat liver. The ionophoric properties were studied using the BLM (black-lipid membrane) method. One novel toxin, forming ion channels permeant to K+ > Na+ > Ca2+, was found and named amylosin. It is produced by B. amyloliquefaciens isolated from indoor air of moisture-damaged buildings. Amylosin was purified with an RP-HPLC and a monoisotopic mass of 1197 Da was determined with ESI-IT-MS. Furthermore, acid hydrolysis of amylosin followed by analysis of the amino acids with the GS-MS showed that it was a peptide. The presence of a chromophoric polyene group was found using a NMR spectroscopy. The quantification method developed for amylosin based on RP-HPLC-UV, using the macrolactone polyene, amphotericin B (MW 924), as a reference compound. The B. licheniformis strains isolated from a food poisoning case produced a lipopeptide, lichenysin A, that ruptured mammalian cell membranes and was purified with a LC. Lichenysin A was identified by its protonated molecules and sodium- and potassium- cationized molecules with MALDI-TOF-MS. Its protonated forms were observed at m/z 1007, 1021 and 1035. The amino acids of lichenysin A were analyzed with ESI-TQ-MS/MS and, after acid hydrolysis, the stereoisomeric forms of the amino acids with RP-HPLC. The indoor air isolates of the strain of B. amyloliquefaciens produced not only amylosin but also lipopeptides: the cell membrane-damaging surfactin and the fungicidal fengycin. They were identified with ESI-IT-MS observing their protonated molecules, the sodium- and potassium-cationized molecules and analysing the MS/MS spectra. The protonated molecules of surfactin and fengycin showed m/z values of 1009, 1023, and 1037 and 1450, 1463, 1493, and 1506, respectively. Cereulide (MW 1152) was purified with RP-HPLC from a food poisoning strain of B. cereus. Cereulide was identified with ESI-TQ-MS according to the protonated molecule observed at m/z 1154 and the ammonium-, sodium- and potassium-cationized molecules observed at m/z 1171, 1176, and 1192, respectively. The fragment ions of the MS/MS spectrum obtained from the protonated molecule of cereulide at m/z 1154 were also interpreted. We developed a quantification method for cereulide, using RP-HPLC-UV and valinomycin (MW 1110, which structurally resembles cereulide) as the reference compound. Furthermore, we showed empirically, using the BLM method, that the emetic toxin cereulide is a specific and effective potassium ionophore of whose toxicity target is especially the mitochondria.

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The Baltic Sea was studied with respect to selected organic contaminants and their ecotoxicology. The research consisted of analyses of total hydrocarbons, polycyclic aromatic hydrocarbons, bile metabolites, hepatic ethoxyresorufin-O-deethylase (EROD) activity, polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs). The contaminants were measured from various matrices, such as seawater, sediment and biota. The methods of analysis were evaluated and refined to comparability of the results. Polyaromatic hydrocarbons, originating from petroleum, are known to be among the most harmful substances to the marine environment. In Baltic subsurface water, seasonal dependence of the total hydrocarbon concentrations (THCs) was seen. Although concentrations of parent polycyclic aromatic hydrocarbons (PAHs) in sediment surface varied between 64 and 5161 ug kg-1 (dw), concentrations above 860 ug kg-1 (dw) were found in all the studied sub-basins of the Baltic Sea. Concentrations commonly considered to substantially increase the risk of liver disease and reproductive impairment in fish, as well as potential effects on growth (above 1000 ug kg-1 dw), were found in all the studied sub-basins of the Baltic Sea except Kattegat. Thus, considerable pollution in sediments was indicated. In bivalves, the sums of 12 PAHs varied on a wet weight basis between 44 and 298 ug kg-1 (ww). The predominant PAHs were high molecular weight and the PAH profiles of M. balthica differed from those found in sediment from the same area. The PAHs were both pyrolytic and petrogenic in origin, and a contribution from diesel engines was found, which indicates pollution of the Baltic Sea, most likely caused by the steadily increasing shipping in the area. The HPLC methods developed for hepatic EROD activity and bile metabolite measurements proved to be fast and suitable for the study of biological effects. A mixed function oxygenase enzyme system in Baltic Sea perch collected from the Gulf of Finland was induced slightly: EROD activity in perch varied from 0.30 14 pmol min-1 mg-1 protein. This range can be considered to be comparable to background values. Recent PAH exposure was also indicated by enhanced levels (213 and 1149 ug kg-1) of the bile metabolite 1-hydroxypyrene. No correlation was indicated between hepatic EROD activity and concentration of 1-hydroxypyrene in bile. PCBs and OCPs were observed in Baltic Sea sediment, bivalves and herring. Sums of seven CBs in surface sediment (0 5 cm) ranged from 0.04 to 6.2 ug kg-1 (dw) and sums of three DDTs from 0.13 to 5.0 ug kg-1 (dw). The highest levels of contaminants were found in the most eastern area of the Gulf of Finland where the highest total carbon and nitrogen content was found and where the lowest percentage proportion of p,p -DDT was found. The highest concentrations of CBs and the lowest concentration of DDTs were found in M. balthica from the Gulf of Finland. The highest levels of DDTs were found in M. balthica from the Hanö Bight, which is the outer part of the Bornholm Basin close to the Swedish mainland. In bivalves, the sums of seven CBs were 72 108 ug kg-1 (lw) and the sums of three DDTs were 66 139 ug kg-1 (lw). Results from temporal trend monitoring showed, that during the period 1985 2002, the concentrations of seven CBs in two-year-old female Baltic herring were clearly decreased, from 9 16 to 2 6 ug kg-1 (ww) in the northern Baltic Sea. At the same time, concentrations of three DDTs declined from 8 15 to 1 5 ug kg-1 (ww). The total concentration of the fat-soluble CBs and DDTs in Baltic herring muscle was shown to be age-dependent; the average concentrations in ten-year-old Baltic herring were three to five-fold higher than in two-year-old herring. In Baltic herring and bivalves, as well as in surface sediments, CB 138 and CB153 were predominant among CBs, whereas among DDTs p,p'-DDD predominated in sediment and p,p'-DDE in bivalves and Baltic herring muscle. Baltic Sea sediments are potential sources of contaminants that may become available for bioaccumulation. Based on ecotoxicological assessment criteria, cause for concern regarding CBs in sediments was indicated for the Gulf of Finland and the northern Baltic Proper, and for the northern Baltic Sea regarding CBs in Baltic herring more than two years old. Statistical classification of selected organic contaminants indicated high-level contamination for p,p'-DDT, p,p'-DDD, p,p'-DDE, total DDTs, HCB, CB118 and CB153 in muscle of Baltic herring in age groups two to ten years; in contrast, concentrations of a-HCH and g-HCH were found to be moderate. The concentrations of DDTs and CBs in bivalves is sufficient to cause biological effects, and demonstrates that long-term biological effects are still possible in the case of DDTs in the Hanö Bight.

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In aquatic environments, endocrine disrupting chemicals (EDCs) that interfere with the endocrinology of males and females form a threat to the maintenance of populations. EDCs are a diverse group of natural and manmade chemicals that already at very low concentrations (at nanogram levels) can have severe effects on reproduction by individuals, e.g. complete sex reversal, feminisation of males, impaired reproduction even resulting in near extinction of populations. With regard to fish, despite the extensive literature on physiological effects of EDCs, very little is known about potential population-level effects. In this thesis, I examined how 17α-ethinyl estradiol (EE2), a synthetic estrogen used in oral contraceptive pills, affects the reproductive behaviour of a marine fish, the sand goby (Pomatoschistus minutus). The aims were fourfold. First, I investigated how exposure to EE2 affects courtship and parental care of sand goby males. Secondly, I looked at effects on the mating system and sexual selection. In the third study, I observed the effects of exposure in a social context where exposed males had to compete with non-exposed males for resources and mates. Finally, I studied the effects of exposure on male-male competition and male aggressive behaviour. This work revealed that EE2 exposure impairs the ability of males to acquire and defend a nest, as well as diminishes the attractiveness of males to females by decreasing their courtship and aggressive behaviour. These effects are harmful for a male whose reproductive success is determined by the ability to compete for limited resources and to attract mates. Furthermore, this thesis showed that selection on male size was relaxed after EE2 exposure and male size had a smaller effect on mating success. These effects can be of a profound nature as they interfere with sexual selection, and may in the long run lead to the loss of traits maintained through sexual selection. The thesis shows that an exposure to environmentally relevant levels of EE2 clearly reduces the chances of individuals to reproduce successfully. Furthermore, it strongly suggests that several types of biomarkers should be used to detect and assess the effects of EDC exposure because severe behavioural effects can sometimes be seen before effects are detectable at the molecular or morphometric level. Behavioural assays should be considered an important complementary tool for the standard ecotoxicological assays because observed behavioural changes have direct and negative effects on fitness, while the connection between changes in molecular expression and fitness may be less obvious.