Can ecological history influence immunomarker responses and antioxidant enzyme activities in bivalves that have been experimentally exposed to contaminants? A new subject for discussion in "eco-immunology" studies

Numerous studies have demonstrated that environmental parameters affect bivalve immunomarkers. In the present study, we tested the hypothesis that clams (Venerupis philippinarum) collected in sites with different environmental conditions respond differently to experimental contaminant exposure. Clams were collected at two sites within the Lagoon of Venice that are influenced differently by both anthropogenic impact and natural conditions: Marghera, which is characterised by relatively high contamination levels and restricted clam fishing, and Chioggia, which is inside a licensed clam culture area that is characterised by lower contamination levels. Total haemocyte count, haemocyte diameter and volume, lysozyme activity in both haemocyte lysate and cell-free haemolymph, superoxide dismutase and catalase activities in gills and digestive glands were measured at time 0 (clam sampling time), after 7 days of acclimation in the laboratory and after 1, 3 and 7 days of copper exposure. Interestingly, statistical analyses (three-way ANOVA and Canonical Correlation Analysis) revealed persistent differences in the biological responses of clams from the two sampling sites before and after copper exposure. Conversely, the influence of copper on cellular and biochemical parameters was negligible. Overall, the results obtained indicated that animals with a different ecological history respond differently to experimental contaminant exposure. In addition, this study suggested that immunomarkers and other biomarkers might be used to determine the origin of fishing products.

Gene transcription and biomarker responses in the clam Ruditapes philippinarum after exposure to ibuprofen

Pharmaceuticals are a class of emerging environmental contaminants that continuously enter aquatic environments. Presently, little information is available about the effects of these substances on non-target organisms, such as bivalves. We investigated the effects of ibuprofen (IBU) on the clam Ruditapes philippinarum. Clams were exposed for 1, 3, 5 and 7 days to 0, 100 and 1000 μgIBU/L, and established biomarker responses (haemolymph lysozyme, gill acetylcholinesterase and digestive gland superoxide dismutase activities) as well as digestive gland transcriptome were evaluated. A two-way ANOVA revealed significant effects of both "IBU concentration" and "exposure duration" on biomarker responses. Overall, the enzyme activities were generally lower in IBU-exposed clams than in controls. Although limited knowledge of the mollusc transcriptome makes it difficult to interpret the effects of IBU on clams, the gene transcription analysis using DNA microarrays enabled the identification of the putative molecular mode of action of the IBU. The functional analysis of differentially transcribed genes suggests that IBU can interfere with various signalling pathways in clams, such as arachidonic acid metabolism, apoptosis, peroxisomal proliferator-activated receptors, and nuclear factor-kappa B. In addition, several genes involved in the metabolism of xenobiotics (e.g., glutathione S-transferase, sulfotransferase, cytochrome P450) were also found to be significantly affected by IBU exposure. In summary, the integrated approach of gene transcription analysis and biomarker responses facilitated the elucidation of the putative mechanisms of action of IBU in non-target species.

Accumulation of selenium in Ulva sp. and effects on morphology, ultrastructure and antioxidant enzymes and metabolites

The impact of selenium (Se) on Ulva sp., a green macroalga naturally growing in the Venice Lagoon, was investigated. The alga was provided for 10 days with concentrations of selenate (Na(2)SeO(4)) ranging from 0 to 100 μM. Se accumulation in the algal biomass was linearly related to the selenate dose and this relationship was not affected by the high sulfate concentration measured in the seawater. The amount of Se measured in the alga was always relatively low and not hazardous to algal consumers. However, Se induced the formation of hydrogen peroxide (H(2)O(2)) in Ulva sp. and, as a result, the activity of antioxidant enzymes (superoxide dismutase, SOD, and catalase, CAT) and the amount of antioxidant metabolites (phenols, flavonoids and carotenoids) increased, even when selenate was supplied to the macroalga at low concentration (2.5 μM). This indicated that different components of the antioxidant defence system played a pivotal role in overcoming oxidative damage by Se in the macroalga, and explained the lack of morphological and ultrastructural alterations in Ulva sp. exposed to selenate.

The nonsteroidal anti-inflammatory drug, ibuprofen, affects the immune parameters in the clam Ruditapes philippinarum

The effects of ibuprofen (IBU) on the immune parameters of the clam Ruditapes philippinarum were investigated after a 7-day exposure to sublethal IBU concentrations (0, 0 + ethanol, 100, 500, and 1000 μg/L). Total haemocyte count (THC), haemocyte diameter and volume, haemocyte proliferation and uptake of the vital dye Neutral Red (NR) were measured. The cytotoxicity (assessed by the lactate dehydrogenase assay, LDH) and the capability of IBU to induce DNA fragmentation (indicative of apoptosis) were also investigated. The exposure of clams to the highest IBU concentration significantly reduced their THC, whereas no significant changes were observed in either the diameter or volume of haemocytes. Significant increases in haemocyte proliferation were recorded in clams that were exposed to the two highest tested concentrations of IBU. Exposure of clams to 1000 μg IBU/L significantly reduced NR uptake and increased haemolymph LDH activity. Conversely, IBU did not induce DNA fragmentation in haemocytes. Although the IBU concentrations tested in this study were higher than those generally recorded in aquatic environments, results obtained indicate that exposure of clams to IBU induces significant alterations in the immune parameters and suggest potential immunosuppression in treated clams.

New evidences in the complexity of contamination of the lagoon of Venice: polybrominated diphenyl ethers (PBDEs) pollution

This study presents the first evaluation of the current pollution by polybrominated diphenyl ethers (PBDEs) of surface sediments from the Lagoon of Venice. We focused the research on tri-to hepta-BDEs, the main components of penta- and octa-mixtures, which are considered to be the most toxic for the biocoenosis. The results pointed out a quite homogeneous contamination of this keystone European transitional environment, with ∑ (13)PBDEs values ranging from 0.39 to 6.78 ng/g dry weight; these values reflect low to moderate pollution levels, which is in conformity to other coastal European ecosystems. The average PBDE profile of the lagoon sediments follows this decreasing trend of congeners: BDE-47>BDE-99> >BDE-190>BDE-28>BDE-153>BDE-154>BDE-138, BDE-183, and BDE-17, which is similar to the worldwide distribution pattern. BDE-47 and BDE-99 revealed a recent use of a penta-BDE mixture, while the presence of hepta-BDEs (BDE-183 and BDE-190) in all of the sites can indicate the actual use of a deca-BDE formulation, because these congeners are considered to be debrominated byproducts of BDE-209 degradation.

First evidence of immunomodulation in bivalves under seawater acidification and increased temperature

Water acidification, temperature increases and changes in seawater salinity are predicted to occur in the near future. In such a global climate change (GCC) scenario, there is growing concern for the health status of both wild and farmed organisms. Bivalve molluscs, an important component of coastal marine ecosystems, are at risk. At the immunological level, the ability of an organism to maintain its immunosurveillance unaltered under adverse environmental conditions may enhance its survival capability. To our knowledge, only a few studies have investigated the effects of changing environmental parameters (as predicted in a GCC scenario) on the immune responses of bivalves. In the present study, the effects of both decreased pH values and increased temperature on the important immune parameters of two bivalve species were evaluated for the first time. The clam Chamelea gallina and the mussel Mytilus galloprovincialis, widespread along the coast of the Northwestern Adriatic Sea, were chosen as model organisms. Bivalves were exposed for 7 days to three pH values (8.1, 7.7 and 7.4) at two temperatures (22 and 28°C). Three independent experiments were carried out at salinities of 28, 34 and 40 PSU. The total haemocyte count, Neutral Red uptake, haemolymph lysozyme activity and total protein levels were measured. The results obtained demonstrated that tested experimental conditions affected significantly most of the immune parameters measured in bivalves, even if the variation pattern of haemocyte responses was not always linear. Between the two species, C. gallina appeared more vulnerable to changing pH and temperature than M. galloprovincialis. Overall, this study demonstrated that climate changes can strongly affect haemocyte functionality in bivalves. However, further studies are needed to clarify better the mechanisms of action of changing environmental parameters, both individually and in combination, on bivalve haemocytes.

A multi-biomarker approach to assess effects of Triclosan in the clam Ruditapes philippinarum

The effects of 7 days' exposure to differing Triclosan (TCS) concentrations (300, 600, and 900 ng/L) were investigated in the clam Ruditapes philippinarum. Vitellogenin (Vg)-like protein levels in haemolymph and digestive gland from males and females, gill acetylcholinesterase (AChE) activity, superoxide dismutase (SOD) and catalase (CAT) activities in gills and digestive gland, and gill lipid peroxidation (LPO) were measured. The highest TCS concentrations decreased significantly Vg levels in male haemolymph and digestive gland, whereas no significant variations were found in females. The highest TCS concentrations increased significantly SOD activity in gills, but decreased it in digestive gland. No changes in CAT activity were observed. In gills, TCS reduced significantly AChE activity, but it did not induce significant variations in LPO. Our study demonstrates that TCS alters biochemical parameters in R. philippinarum, even at environmentally realistic concentrations, and suggests differing modes of action of the contaminant, in clams at least.

Immunotoxic effects of triclosan in the clam Ruditapes philippinarum

The effects of Triclosan (TCS) on the immune parameters of the clam Ruditapes philippinarum were investigated after a 7-day exposure to sublethal TCS concentrations (300, 600, and 900 ng l(-1)). Hemocytes from controls and exposed clams were collected, and the effects of TCS on total hemocyte count (THC), hemocyte diameter and volume, uptake of the vital dye Neutral Red (an indicator of pinocytosis), lysozyme activity, and proliferation were evaluated. The cytotoxicity, which was evaluated using the lactate dehydrogenase assay, and the capability of TCS to induce DNA fragmentation, which indicated apoptosis, were also investigated. The exposure of clams to all tested TCS concentrations significantly decreased THC, whereas the highest tested TCS concentration significantly reduced the diameter and volume of hemocytes. TCS negatively affected pinocytosis and the proliferation of hemocytes, but it did not alter hemocyte lysozyme activity. TCS exerted cytotoxic effects and induced DNA fragmentation in hemocytes of R. philippinarum. Overall, these results suggest a relationship between TCS exposure and changes in the measured immune parameters and indicate immunosuppression in TCS-treated clams.

In vitro effects of nonylphenol on functional responses of haemocytes of the colonial ascidian Botryllus schlosseri

The effects of nonylphenol (NP) on functional responses of haemocytes of the colonial ascidian Botryllus schlosseri were evaluated. Haemocytes were exposed to 0.1, 1 and 10 μM NP and the effects on haemocyte viability, adhesion, morphology, lysosomal membrane stability, phagocytic activity and early apoptosis were evaluated. Haemocyte viability and adhesion were not affected by NP. Phagocytic activity and the amoebocytic index decreased significantly at all the concentrations tested, while exposure of haemocytes to 1 and 10 μM NP caused a significant increase in the diffusion of Neutral Red into the cytosol. The percentage of cells positive to Annexin-V (indicative of early apoptosis) increased significantly at 1 and 10 μM NP. Results obtained suggested a relationship between NP and alterations in functional responses of haemocytes in B. schlosseri. Biomarkers measured resulted sensitive, rapid and reproducible, even if their responsiveness will be evaluated after in vivo exposure of animals to NP.

Effects of temperature on cellular and biochemical parameters in the crab Carcinus aestuarii (Crustacea, Decapoda)

The effects of temperature on cellular and biochemical parameters of the crab Carcinus aestuarii were evaluated. Crabs were kept for 7 days at 4, 17 (reference value) and 30 °C (salinity of 35 psu), and total haemocyte count (THC), haemocyte volume, haemocyte proliferation, phenoloxidase (PO) activity in both haemocyte lysate (HL) and cell-free haemolymph (CFH), CFH total protein and glucose levels, superoxide dismutase (SOD) and catalase (CAT) activities in both gills and digestive gland were evaluated. The lowest and the highest temperature significantly decreased THC, whereas haemocyte volume and haemolymph glucose concentration did not differ significantly among experimental conditions. Haemolymph protein concentration significantly reduced in crabs maintained at 30 °C, when compared with that of animals kept at 4 and 17 °C. Haemocyte proliferation increased significantly in crabs kept at 4 and 30 °C, when compared with that of crabs held at 17 °C. Likewise, a significantly higher PO activity was recorded in CFH from crabs kept at 4 and 30 °C, than in control crabs. Conversely, PO activity did not vary significantly in HL. With regard to antioxidant enzyme activities, a significant decrease in CAT activity was observed in gills from crabs kept at 4 °C, when compared to that of crabs kept at 17 °C and 30 °C. Results obtained demonstrated that the highest and lowest temperature tested influenced crab biological responses, and indicated that C. aestuarii modulated its cellular and biochemical parameters (mainly haemocyte proliferation, CFH protein concentrations and CFH PO activity) in order to cope with temperature.

Combined effects of temperature and salinity on functional responses of haemocytes and survival in air of the clam Ruditapes philippinarum

The combined effects of temperature and salinity on both immune responses and survival in air of the clam, Ruditapes philippinarum, were evaluated for the first time. The animals were kept for 7 days at three differing temperature (5 °C, 15 °C, 30 °C) and salinity values (18 psu, 28 psu, 38 psu), and effects of the resulting 9 experimental conditions on total haemocyte count (THC), Neutral Red uptake (NRU), haemolymph protein concentration, and lysozyme activity in both haemocyte lysate (HL) and cell-free haemolymph (CFH) were evaluated. The survival-in-air test was also performed. Two-way ANOVA analysis revealed that temperature influenced significantly THC and NRU, whereas salinity and temperature/salinity interaction affected NRU only. Temperature and salinity did not influence significantly HL and CFH lysozyme activity, as well as haemolymph total protein content. Survival-in-air test is widely used to evaluate general stress conditions in clams. In the present study, temperature and salinity were shown to influence the resistance to air exposure of R. philippinarum. The highest LT₅₀ (air exposure time resulting in 50% mortality) value was recorded in clams kept at 18 psu and 15 °C, whereas the lowest value was observed in clams kept at 28 psu and 30 °C. Overall, results obtained demonstrated that temperature and salinity can affect some functional responses of haemocytes from R. philippinarum, and suggested a better physiological condition for animals kept at 15 °C temperature and 18 psu salinity.

Can starvation influence cellular and biochemical parameters in the crab Carcinus aestuarii?

Crustacea experience periods of starvation during moulting or when limited food availability occurs. The effects of starvation on Crustacea physiological responses have been demonstrated, whereas the effects of starvation on Crustacea immune parameters remain to be more fully studied. In the present study the effects of starvation on immune parameters and antioxidant enzyme activities of the crab Carcinus aestuarii were evaluated for the first time. Treated crabs were starved for 7 days, whereas control crabs were fed daily with mussels. Total haemocyte count (THC), haemocyte diameter and volume, haemocyte proliferation, cell-free haemolymph (CFH) glucose and total protein levels, and phenoloxidase (PO) activity in both haemocyte lysate (HL) and CFH were measured in crabs. In addition, superoxide dismutase (SOD) and catalase (CAT) activities were evaluated in both gills and digestive gland from crabs, in order to evaluate whether starvation induced oxidative stress in C. aestuarii. THC increased significantly in starved crabs, with respect to controls, whereas no significant variations were observed in haemocyte diameter, volume and proliferation. In CFH of starved animals glucose concentration significantly increased, whereas total protein concentration significantly reduced. A significantly higher PO activity was recorded in HL from starved crabs, than in control crabs. Conversely, PO activity did not vary significantly in CFH. Starvation did not cause significant alterations in antioxidant enzyme activities in both gills and digestive gland. Results obtained demonstrated that starvation influenced crab immune parameters, but did not induce oxidative stress. Results also indicated that C. aestuarii can modulate its cellular and biochemical parameters in order to cope with starvation.

The role of haemocytes from the crab Carcinus aestuarii (Crustacea, Decapoda) in immune responses: A first survey

For the first time, a functional study of haemocytes from the crab Carcinus aestuarii was performed in order to evaluate their involvement in immune responses. Total haemocyte count (THC), phagocytosis, haemolymph opsonisation properties, hydrolytic and oxidative enzyme activities, and production of intracellular superoxide anion were evaluated. A great variability in THC was recorded among individuals, and haemocyte mean number was 6.4 (x10(6)) cells/ml haemolymph. Although only hyalinocytes were able to phagocytose yeast cells or Zymosan, phagocytic index was low (3%) and did not increase significantly (4%) after pre-incubation of yeast and Zymosan in cell-free haemolymph, suggesting that haemolymph did not have opsonising properties. All haemocyte types produced superoxide anion, whereas only granulocytes were positive to the hydrolytic enzymes assayed. In addition, only granulocytes were positive to phenoloxidase activity. Both Petri dish and spectrophotometric assays revealed a very low lysozyme-like activity in cell-free haemolymph (CFH) and haemocyte lysate (HL), although enzyme activity was higher in CFH than in HL. Interestingly, normalisation of data as to total protein content in CFH and HL resulted in an opposite situation, lysozyme-like activity being higher in HL than in CFH. This demonstrated that haemolymph of C. aestuarii has a high quantity of total proteins, functional properties of which need to be better investigated in future studies. Overall, the results obtained in the present study indicated that C. aestuarii haemocytes are not very active phagocytic cells, but they are more active in terms of both hydrolytic and oxidative enzyme activities and superoxide anion production.

Biomarker responses and contamination levels in crabs (Carcinus aestuarii) from the Lagoon of Venice: An integrated approach in biomonitoring estuarine environments

An integrated biological-chemical approach is necessary to evaluate correctly the environmental status of bodies of water, as suggested by the EU Water Framework Directive. The shore crab Carcinus aestuarii, sampled in the Lagoon of Venice (NE Italy), was used as a biomonitor species, and the chemical concentrations of 42 organic pollutants (HCHs, PAHs, PCBs, DDTs, PBDEs), biological responses related to neurotoxicity (AChE inhibition), detoxification mechanisms (CYP450 induction) and endocrine alterations (vitellogenin-like protein induction) were measured at the same time. The responsiveness of biomarkers as predictors (or descriptors) of chemical contamination was evaluated by multivariate regression analysis, revealing good predictor potential for the selected biomarkers. Biomonitoring in the Lagoon of Venice revealed a predominance of DDT and PCB compounds, especially near industrial sites or large cities. Endocrine alterations, not always correlated with the presence of measured compounds, were also detected in many areas, suggesting exposure to compounds able to interfere with the crab endocrine system.

First cytochemical study of haemocytes from the crab Carcinus aestuarii (Crustacea, Decapoda)

For the first time, a morphological study of haemocytes from the crab Carcinus aestuarii was carried out by means of light microscopy and differing cytochemical assays. Analysis of haemocyte size frequency distribution (performed by means of a Coulter Counter) revealed the presence of two distinct haemocyte fractions in C. aestuarii haemolymph, depending on cell size. The first fraction was of about 3–5 µm in diameter and 30–50 fL in volume, the second was of about 6–12 µm in diameter and over 200 fL in volume. Mean cell diameter and volume were 8.20±1.7 µm and 272.30±143.5 fL, respectively. Haemocytes observed under light microscope were distinguished in three cell types: granulocytes (28%; 11.94±1.43 µm in diameter) with evident cytoplasmic granules, semigranulocytes (27%; 12.38±1.76 µm in diameter) with less granules than granulocytes, and hyalinocytes (44%; 7.88±1.6 µm in diameter) without granules. In addition, a peculiar cell type was occasionally found (about 1%): it was 25–30 µm in diameter and had a great vacuole and a peripheral cytoplasm with granules. Granulocyte and semigranulocyte granules stained in vivo with Neutral Red, indicating that they were lysosomes. Giemsa’s dye confirmed that granulocytes and semigranulocytes were larger than hyalinocytes. Pappenheim’s panoptical staining and Ehrlich’s triacid mixture allowed to distinguish granule-containing cells (including semigranulocytes) in acidophils (64%), basophils (35%) and neutrophils (1%). Hyalinocytes showed always a basophilic cytoplasm. Haemocytes were positive to the PAS reaction for carbohydrates, even if cytoplasm carbohydrate distribution varied among cell types. Lastly, lipids were found on cell membrane and in cytoplasm of all haemocyte types in the form of black spots produced after Sudan Black B staining. The morphological characterisation of C. aestuarii haemocytes by light microscopy was necessary before performing both ultrastructural and functional studies of circulating cells.

Biomarker responses in the crab Carcinus aestuarii to assess environmental pollution in the Lagoon of Venice (Italy)

In the present study, three biomarkers, acetylcholinesterase (AChE) activity, vitellogenin (Vg)-like proteins, and ethoxyresorufin O-deethylase (EROD) activity, were evaluated in male Carcinus aestuarii crabs collected from four sites in the Lagoon of Venice, two in the northern lagoon area and two in the southern one. Results revealed differences among sites in relation to each specific biomarker. Hence, a suite of biomarkers can be used to discriminate sampling sites according to types of pollution, reflecting differing conditions of anthropogenic impact. Comparisons between the northern and southern lagoon areas suggest that the latter are in better condition for Vg-like protein level and AChE activity. The lower EROD activity recorded in crabs from the northern sites suggests a detrimental inhibitory effect of contaminants, rather than a lack of induction due to lower pollution levels.

Investigation of EROD, CYP1A immunopositive proteins and SOD in haemocytes of Chamelea gallina and their role in response to B[a]P

CYP1A sub-family represents the main form of cytochrome P450 involved in benzo[a]pyrene (B[a]P) detoxification, but there are no clear evidences about its presence in invertebrates. 7-Ethoxy resorufin O-deethylase (EROD) activity is strictly related to CYP1A presence, at the same time P450-dependent oxidative metabolism leads to reactive oxygen species (ROS) production, thought to be an important mechanism of pollutant-mediated toxicity in aquatic organisms. Superoxide dismutases (SODs), EROD and CYP1A activities and/or expressions were detected in haemocytes of pooled clams (Chamelea gallina) and cell-free haemolymph after 24 h, 7 and 12 days of exposure to 0.5 mg/L of B[a]P. After 24 h, B[a]P content was maximum in whole tissues. A 61 kDa band was recognized in haemocytes and cell-free haemolymph by polyclonal anti-fish CYP1A, while 53.5 and 63.8 kDa CYP1A immunopositive proteins were discriminate without differences of expression. Differently, EROD, MnSOD activity/expression and ECSOD expression decreased in haemocytes and haemolymph. C. gallina immune system presents an interesting response dose/time exposure of B[a]P and the 7 days condition highlights the major effects of xenobiotic action. The identification of basal EROD levels supports the possible presence of the CYP1A, never identified in C. gallina and more specifically never isolated in immune cells, as confirmed by CYP1A-immunopositive proteins identification.

First evidence of altered immune responses and resistance to air exposure in the clam Chamelea gallina exposed to benzo(a)pyrene

Effects of benzo(a)pyrene [B(a)P] (at a nominal concentration of 0.5 mg/L) on immune responses of the clam Chamelea gallina were investigated after 1, 7, and 12 days exposure. Total hemocyte count (THC), hemocyte volume, phagocytic activity, lysozyme-like activity in both hemocyte lysate (HL) and cell-free hemolymph (CFH) were measured. As unexpected alterations in hemocyte adhesion capability were observed in short-term hemocyte cultures for phagocytosis assays after a 1-day exposure, an adhesion test (not included in the original experimental setup) was performed after 7 and 12 days of exposure only. The survival-in-air test was carried out to evaluate general stress conditions in B(a)P-exposed clams. No alterations in THC was observed, whereas exposure for 7 and 12 days to B(a)P significantly decreased phagocytic activity and adhesion capability when compared with controls. Significant decreases in lysozyme activity were observed in CFH and HL, with respect to controls. B(a)P was also shown to alter the resistance to air exposure of clams. The LT(50) values fell from 9 days in control clams to 7 days in 1-day-exposed animals, and from 6 days in control clams to 5 days in 7-day-exposed bivalves. No significant variations in LT(50) values were recorded after 12 days of exposure. Results highlight a relationship between B(a)P exposure and alterations in hemocyte functionality and suggest that the contaminant induced irreversible immunosuppression in C. gallina, by altering phagocytic activity, adhesion capability, and enzymatic activity. Conversely, reduction in resistance to air exposure was reversible, suggesting that impairment of important physiological functions of clams occurred in the first phases of exposure only.

Can 17-β estradiol induce vitellogenin-like proteins in the clam Tapes philippinarum?

Estrogenic potency of 17-β estradiol (E2) was evaluated for the first time in both sexually undifferentiated (during resting phase, at the very early stage of gametogenesis) and differentiated (in pre-spawning phase) clams (Tapes philippinarum), following waterborne exposure for 7 and 14 days to various E2 concentrations (0, 0+acetone, 5, 25, 50, 100 and 1000ng/L). Vitellogenin (Vg)-like protein levels were evaluated in both haemolymph and digestive glands by the alkali-labile phosphate (ALP) assay. In the resting phase of clams, exposure for 7 days to all E2 concentrations tested resulted in significant increases in ALP in haemolymph with respect to controls. Conversely, no statistically significant differences were observed in digestive gland from E2-exposed bivalves, compared with controls. After 14-days exposure, ALP significantly increased in haemolymph from 1000ng E2/L-exposed clams and in digestive gland from 5ng E2/L-exposed animals. Interestingly, in the pre-spawning phase of clams, significant decreases in ALP levels were recorded in haemolymph from females exposed for 7 days, whereas no differences were observed in males. No significant variations were observed in ALP content in digestive gland from both females and males. ALP levels in haemolymph were shown to increase significantly in females exposed for 14 days to 50ng E2/L, and in males exposed to 100ng E2/L. Exposure for 14 days to all the E2 concentrations tested resulted in significant increases of ALP levels in the digestive gland of females. Conversely, variations in ALP content of male digestive glands were not significant. Results obtained appeared controversial and somewhat difficult to explain. Indeed, no univocal response by clams was observed after 7 and 14 days exposure to E2. Further studies need to elucidate the role of E2 in promoting Vg induction in clams.

Vitellogenin as a biomarker of exposure to estrogenic compounds in aquatic invertebrates: a review

Vitellogenins (Vg) are the major precursor of the egg-yolk proteins, vitellins (Vn), which provide energy reserves for embryonic development in oviparous organisms. In mature females, Vg are generally synthesised in response to endogenous estrogens, such as 17beta-estradiol (E2), released into the bloodstream and then stored in developing oocytes. In males, the Vg gene, although present, is normally silent. However, it may be activated by (xeno)-estrogens. These substances belong to a large and heterogeneous group of environmental contaminants capable of altering endocrine functions in organisms. For this reason, they are named endocrine disrupting chemicals (EDCs). Natural steroidal estrogens [E2, estrone (E1), estriol (E3)] and synthetic chemicals, such as pesticides, polychlorinated biphenyls (PCBs) and household products (surfactants) are estrogenic compounds widespread in aquatic ecosystems. The main sources of contamination mostly stem (or originate) from municipal and industrial effluents, agricultural practices, livestock wastes and sewage treatment plants (STP). Recently, Vg induction, mainly in males and immature females, has been proposed as a useful biomarker to assess estrogenic contamination in aquatic environments. Indeed, estrogenicity of individual chemicals and mixtures has extensively been evaluated, in both laboratory and field studies, albeit mostly in fish. In contrast, limited attention has centred on evaluating xenoestrogen effects in aquatic invertebrates, probably owing to limited knowledge of their endocrinology. This review focuses on a brief description of xenoestrogens and their occurrence in aquatic environments, and on Vg induction in aquatic invertebrates in response to both experimental and environmental exposure to estrogenic compounds. Results of recent field and laboratory studies are presented. In addition, new perspectives about the use of Vg induction as a biomarker of exposure to estrogenic compounds are also discussed.

Effects of 4-nonylphenol exposure in mussels (Mytilus galloprovincialis) and crabs (Carcinus aestuarii) with particular emphasis on vitellogenin induction

Since it is often difficult to estimate possible adverse effects due to contamination in selected ecosystems, multi-species biomonitoring may provide more information, taking into account different routes of exposure, ecological roles and metabolic capabilities of animals. In this context, we exposed for 7 days the mussel Mytilus galloprovincialis and the crab Carcinus aestuarii to 4-nonylphenol (NP), a well-known xenoestrogen. In mussels (0-0.2 mg NP l(-1)), we measured NP bioaccumulation in soft tissues and vitellogenin (Vg)-like protein levels in digestive glands from both males and females by the alkali-labile phosphate assay (ALP). As no reference data were available for crab exposure, the NP 96-h LC(50) value was previously determined. Then, in sublethally exposed (0-1.0 mg NP l(-1)) male crabs, NP bioaccumulation and Vg levels were measured in hemolymph, gonads and digestive gland. Bioaccumulation of NP increased from 43 to 371 microg g(-1) d.w. in mussels, and from 3.6 to 37 microg g(-1) d.w. in crabs, depending on the NP concentration in water. Dose-dependent Vg-like protein induction was observed in both species, appearing to be related to NP bioaccumulation, although a partial decrease was recorded at the highest concentration tested. A similar trend was observed in both digestive gland and gonad of exposed crabs; Vg increased to a lesser extent, although significantly, in hemolymph. Results demonstrated that NP induces Vg synthesis both in male and female mussels, as well as in male crabs. On the basis of the responsiveness of both species investigated, a multi-species approach is indicated in biomonitoring programmes.

Immunotoxicity of the xenoestrogen 4-nonylphenol to the cockle Cerastoderma glaucum

The in vivo effects of 4-nonylphenol (NP) on functional responses of haemocytes from the cockle Cerastoderma glaucum were investigated after 7 days exposure to sublethal NP concentrations (0, 0+acetone, 0.0125, 0.025, 0.05 and 0.1 mg/l NP). Haemocytes from both controls and exposed cockles were collected, and the effects of NP on total haemocyte count (THC) and volume of circulating cells, intracellular superoxide anion (O(2)(-)) levels, acid phosphatase and lysozyme-like activities in both haemocyte lysate (HL) and cell-free haemolymph (CFH) were evaluated. Exposure of cockles to 0.1mg/l NP significantly increased THC (p<0.05) with respect to controls. Analysis of haemocyte size frequency distribution showed that the haemocyte fraction of about 7-8 microm in diameter and 250 femtolitres in volume increased markedly in cockles exposed to the highest NP concentration tested. Apoptosis resulting in cell volume reduction in NP-exposed animals cannot be excluded. No statistically significant variation in intracellular O(2)(-) levels was observed. Conversely, significant increases (p<0.05) in acid phosphatase activity were observed in CFH from 0.05 and 0.1mg/l NP-exposed animals; no significant differences in enzyme activity were recorded in HL. Lysozyme-like activity also increased significantly in CFH from cockles exposed to 0.05 mg/l NP (p<0.05) and 0.1 mg/l NP (p<0.001). Instead, lysozyme-like activity decreased significantly (p<0.05) in the HL of animals exposed to 0.05 mg/lNP. Our results suggest that NP induces variations in the functional responses of haemocytes of C. glaucum, mainly by reducing cell membrane stability and promoting cell degranulation.

Lethal and estrogenic effects of 4-nonylphenol in the cockle Cerastoderma glaucum

The lethal and sublethal effects of the xenoestrogen 4-nonylphenol (NP) were evaluated in the cockle Cerastoderma glaucum. In a 96-h lethality test, bivalves were exposed to 0, 0+ acetone, 0.19, 0.38, 0.75, 1.5 and 3.0 mg NP/l. The 96-h LC(50) value was 0.3mg NP/l. No mortality was observed at 0.1 mg NP/l. The potential estrogenicity of NP was studied in both sexually undifferentiated (resting phase) and differentiated (pre-spawning phase) cockles, exposed for 7 and 14 days to 0, 0+ acetone, 0.0125, 0.025, 0.05, and 0.1 mg NP/l. Vitellogenin (Vg)-like protein levels were determined in both haemolymph and digestive gland by the alkali-labile phosphate (ALP) assay. In the resting phase, exposure for 7 days to 0.1 mg NP/l resulted in significant increases in ALP in both haemolymph and digestive gland, compared with controls. A significant increase was also observed in digestive gland of animals exposed to 0.0125 mg NP/l-exposed animals. After 14 days of exposure, haemolymph ALP levels were significantly increased in exposed animals at all NP concentrations tested, whereas no difference was recorded in digestive gland. In the pre-spawning phase, exposure for 7 days to NP significantly increased ALP levels in haemolymph from males exposed at all NP concentrations tested, whereas no significant variations were found in haemolymph from females. NP (0.05 and 0.1 mg/l) was also shown to increase ALP concentrations significantly in digestive gland of males, but not in those of females. Likewise, after 14 days' exposure, ALP levels significantly increased in haemolymph from males only at 0.1 mg NP/l. Conversely, NP caused significant increases in ALP levels in digestive gland from both males (at all NP concentrations tested) and females (at 0.025 and 0.1 mg NP/l). These results demonstrate that NP induces Vg synthesis in C. glaucum. Interestingly, males were more responsive to NP than females.

Uptake and elimination of 4-nonylphenol by the clam Tapes philippinarum

The present study is the first dealing with the accumulation and elimination of 4-nonylphenol (NP) by the Manila clam, Tapes philippinarum. Specimens of T. philippinarum were exposed to NP-spiked seawater, and the NP contents in whole soft tissue, gills, digestive gland, and haemolymph were measured. Actual NP concentrations in seawater and microalgae (Isochrysis galbana) used for feeding were also determined, and the algal bioconcentration factor (BCF) value (640 ml/g) was calculated. Volatilisation was the main cause of dissipation of NP from experimental tanks, attaining up to 78% of the NP added. NP accumulated by algae used for feeding was negligible with respect to the total added NP, and we concluded that in our experiments, clams accumulated NP mainly from water and not food intake. Accumulation followed a two-compartment, first-order rate coefficient model, with an uptake rate coefficient of 13.8 +/- 0.6 mL g(-1)h(-1)(fresh weight [fw]) and an elimination coefficient of 0.0070 +/- 0.0005 h(-1). Ninety percent of the steady state was reached after 14 days of exposure, and the BCF value at the steady state was 1958 +/- 158 mL g(-1) fw (1.8 +/- 0.2 x 10(5) based on lipid weight). Slightly less than 50% of NP bioaccumulated through water was allocated into the gills, whereas the rest was found in the digestive gland. In the first 8 hours, clams eliminated 51% of the NP accumulated, and only 2% of the NP accumulated was detected in the clams at the end of the elimination phase (day 14). Two-compartment first-order decay model described the elimination of the accumulated NP by considering the clam as two compartments each with a different elimination rate. The sudden elimination of NP in the initial hours can be attributed to the elimination of NP accumulated into the gills and readily available for excretion (k ( e ) = 0.30 +/- 0.07 h(-1)). The slower step of the elimination process should be the mobilisation of NP accumulated in internal organs, which must be carried into the haemolymph for excretion (k(e) = 0.0091 +/- 0.0002 h(-1)). Because T. philippinarum has been demonstrated to accumulate NP dissolved in water, high NP levels can be hypothesised in clams from highly contaminated environments. This research was performed according to all national and international guidelines for animal welfare.

Haemocytes and blastogenetic cycle in the colonial ascidian Botryllus schlosseri: a matter of life and death

A recurrent blastogenetic cycle characterizes colonies of the ascidian Botryllus schlosseri. This cycle starts when a new zooid generation opens its siphons and ends with take-over, when adult zooids cease filtering and are progressively resorbed and replaced by a new generation of buds, reaching functional maturity. During the generation change, massive apoptosis occurs in the colony, mainly in the tissues of old zooids. In the present study, we have investigated the behaviour of haemocytes during the colonial blastogenetic cycle, in terms of the occurrence of cell death and the expression of molecules involved in the induction of apoptosis. Our results indicate that, during take-over, caspase-3 activity in haemocyte lysates increases. In addition, about 20%-30% of haemocytes express phosphatidylserine on the outer leaflet of their plasma membrane, show DNA fragmentation and are immunopositive for caspase-3. Senescent cells are quickly ingested by circulating phagocytes that frequently, having once engulfed effete cells, in turn enter apoptosis. Dying cells and corpses are replaced by a new generation of cells that appear in the circulation during the generation change.

First evidence of altered vitellogenin-like protein levels in clam Tapes philippinarum and in cockle Cerastoderma glaucum from the Lagoon of Venice

Possible xenoestrogenic effects were investigated, for the first time, in two bivalve species from the Lagoon of Venice (Italy): the clam Tapes philippinarum and the cockle Cerastoderma glaucum. Bivalves were collected far from their reproductive phase at the very early stage of gametogenesis (January), and in the pre-spawning period (June) in six sites. Vitellogenin (Vg)-like proteins (a biomarker of exposure to estrogenic compounds) were measured by the alkali-labile phosphate method (ALP), in both haemolymph and digestive gland from males and females (when it was possible to distinguish sex by microscopic observation of gonadal tissue). Haemolymph calcium concentrations (a parameter considered closely related to the presence of Vg-like proteins) and the bivalve condition index (CI) were also measured. In both seasons, bivalves collected at Campalto (near a sewage treatment plant) and Marghera (a highly contaminated area) had higher Vg-like protein levels, particularly in haemolymph, than animals from the other sampling sites. Interestingly, CI had high values in these polluted sites. In June only, Vg-like proteins and Ca(2+) levels in haemolymph exhibited similar trends in both bivalve species at most sampling sites. The responsiveness of bivalves to environmental xenoestrogens was higher in June, allowing better discrimination among sites. The present study demonstrates that animals from highly polluted areas have increased Vg-like protein levels. As endocrine disruption due to exposure to estrogenic compounds may cause fertility reduction, alterations in the sex ratio, and a decrease in reproductive rate, a condition of potential risk for bivalve populations in estuarine areas is highlighted.

Haemocytes of the cockle Cerastoderma glaucum: morphological characterisation and involvement in immune responses

For the first time, morpho-functional characterisation of haemocytes from the cockle Cerastoderma glaucum was performed to identify circulating cell types and to study their involvement in immune responses. Haemocyte mean number was 5.5 (x 10(5)) cells/mL haemolymph. Two main haemocyte types were found in haemolymph: granulocytes (85%), about 10 microm in diameter and with evident cytoplasmic granules, and hyalinocytes (15%), 8 to 14 microm in diameter, with a few or no granules. Most of the cytoplasmic granules stained in vivo with Neutral Red, indicating that they were lysosomes. On the basis of haemocyte staining properties, granulocytes and hyalinocytes were further classified as basophils and acidophils. Acidophil hyalinocytes were the largest haemocyte type (about 14 microm in diameter) and had an eccentric nucleus and a large cytoplasmic vacuole. Both granulocytes and hyalinocytes (except acidophils) were able to phagocytise yeast cells, although the basal phagocytic index was very low (about 2%). It increased significantly (up to 26%) after pre-incubation of yeast in cell-free haemolymph, suggesting that haemolymph has opsonising properties. Haemocytes also produced superoxide anion. Moreover, both granulocytes and hyalinocytes (except acidophils) were positive for some important hydrolytic and oxidative enzymes. Lysozyme-like activity was recorded in both cell-free haemolymph and haemocyte lysate, although enzyme activity in cell lysate was significantly higher. Results indicate that haemocytes from C. glaucum are effective cells in immune responses.

Effects of high temperatures on functional responses of haemocytes in the clam Chamelea gallina

The effects of high temperatures on the clam, Chamelea gallina, generally recognised as a low tolerant bivalve species, were studied by evaluating some functional responses of the haemocytes. The animals were kept for 7days at 20, 25 and 30 degrees C and total haemocyte count (THC), phagocytosis, lysozyme activity (in both haemocyte lysate and cell-free haemolymph), activity and expression of the antioxidant enzyme superoxide dismutase (SOD) (in both haemocyte lysate and cell-free haemolymph) were chosen as biomarkers of exposure to high temperatures. The survival-in-air test was also performed. During the experiment, the clams showed differing burrowing behaviour: the animals kept at 20 and 25 degrees C burrowed completely, whereas at 30 degrees C the clams progressively emerged from the sediment and then remained on the surface. The highest temperature significantly increased THC, whereas it decreased the phagocytic activity of haemocytes. The haemocyte size frequency distribution in clams kept at 30 degrees C showed that the cell population of about 8-10microm was markedly reduced compared to clams kept at 20 and 25 degrees C. In clams maintained at 25 degrees C, lysozyme activity was significantly increased in haemocyte lysate, whereas it was markedly decreased in cell-free haemolymph. Total SOD activity significantly decreased in haemocytes from clams held at 30 degrees C whereas it increased in cell-free haemolymph from clams held at 25 degrees C and 30 degrees C. A significant decrease in haemocyte Mn-SOD and Cu/Zn-SOD activities was found with increasing temperature. In cell-free haemolymph, the highest Mn-SOD activity was recorded at 30 degrees C, whereas the Cu/Zn-SOD activity showed no significant changes in clams maintained at different temperatures. SOD isoform expression exhibited different patterns in haemocyte lysate and cell-free haemolymph. The resistance to air exposure of clams kept at 30 degrees C was shown to decrease significantly, LT(50) values fell from 6days in clams kept at 20 degrees C and 25 degrees C to 4days in those kept at 30 degrees C.

Acetylcholinesterase as a biomarker of exposure to neurotoxic compounds in the clam Tapes philippinarum from the Lagoon of Venice

Measurement of acetylcholinesterase (AChE) is widely used as a biomarker of exposure to neurotoxic compounds in aquatic environments. In the present study, AChE activity was monitored in the clam Tapes philippinarum in the Lagoon of Venice, with the aim of evaluating the possible exposure of animals to neurotoxic compounds. Two sampling strategies were followed. In the first case, temporal and spatial variations of AChE activity were measured in clams collected seasonally (from October 2003 to June 2004) in 3 sites of the Lagoon: Campalto (site 1), near a sewage treatment plant, Marghera (site 2), a highly polluted area, and Poveglia (site 3), a reference site. The condition index (CI) of clams was also calculated. In the second case, AChE activity was measured in clams collected at the end of seasonal samplings in 12 sites located throughout the Lagoon: areas licensed for clam farming (sites 5 to 11), nearby canals characterised by waste waters from agricultural areas (sites 4, 12, 13, 14), and a reference site outside the Lagoon (site 15). Results revealed a significant reduction in AChE activity in clams from Marghera in October, January and April, indicating their probable exposure to neurotoxic compounds originating in the industrial zone of Porto Marghera. A seasonal trend in AChE activity was also observed, enzyme activity being higher in January and lower in June. Clams from Campalto generally had higher CI values than those from Marghera and Poveglia. However, no particular correlation between AChE activity and CI was found. Lastly, marked differences in AChE activity were recorded when comparing enzyme activity of clams from various sites in the Lagoon of Venice with those of clams collected at site 15. Significant reductions in AChE activity were observed in animals collected in both nearby canals and licensed areas, indicating the homogeneous spatial distribution of potentially neurotoxic compounds throughout the Lagoon. It is probable that sediment mobilisation caused by clam harvesting and the passage of shipping plays an important role in resuspension of persistent contaminants having neurotoxic activity.

Can 4-nonylphenol induce vitellogenin-like proteins in the clam Tapes philippinarum?

Vitellogenins (Vg) are precursors of egg-yolk proteins (vitellins) constituting energy reserves for embryos. In oviparous females, Vg are produced in the liver (or equivalent organs) under the control of endogenous estrogens, released into the bloodstream (plasma or hemolymph), and stored in developing oocytes. Although Vg levels are generally undetectable in male plasma, they may significantly increase in (xeno-)estrogen-exposed males. The aim of the present study was to evaluate estrogenic effects of 4-nonylphenol (NP) in sexually differentiated males and females of the Manila clam Tapes philippinarum. Clams were exposed for 7 days to various sublethal NP concentrations (0, 0+acetone, 0.025, 0.05, 0.1, and 0.2 mg NP/L) and Vg-like protein levels were evaluated in both hemolymph and digestive glands of mollusks by the alkali-labile phosphate assay. This method, based on the determination of phosphates released by Vg, has previously been used to detect Vg concentrations in both fish plasma and bivalve hemolymph. Although Vg levels were generally higher in both hemolymph and digestive gland of T. philippinarum females, males appeared to be more sensitive than females to the estrogenic effects of NP. In males exposed to 0.1 and 0.2 mg NP/L, Vg levels increased significantly in both hemolymph (P < 0.05 and P < 0.01, respectively) and digestive gland (p < 0.05), whereas no changes were observed in those of females. Although the mechanisms by which NP exerts its in vivo endocrine-modulating effects in bivalve mollusks remain unclear, the results of this study demonstrate that NP may induce Vg-like proteins in T. philippinarum, particularly males.

Exposure of the clam Tapes philippinarum to 4-nonylphenol: changes in anti-oxidant enzyme activities and re-burrowing capability

The effects of 4-nonylphenol on anti-oxidant enzyme (superoxide dismutase and catalase) activity in both gills and digestive gland and re-burrowing capability of the clam Tapes philippinarum were investigated after 7 days' exposure to various sublethal concentrations of nonylphenol (NP). NP caused a significant decrease in superoxide dismutase activity in both tissues from the lowest concentration tested, whereas no significant alteration with respect to controls was observed in catalase activity. NP effects on re-burrowing of clams were evaluated in two experiments. In the first, clams exposed to the highest NP concentrations showed a marked delay in re-burrowing 48 h after the end of exposure. Modifications in normal burrowing behaviour were also observed, suggesting that NP acts via narcosis and/or neurotoxic mechanisms. In the second experiment, the elapsed time for 50% of the exposed clams to re-burrow into the sediment (RT(50)) was also calculated in a 24-h re-burrowing response test. At the highest NP concentrations, it was not possible to estimate RT(50) values, as the percentage of clams showing complete burial was less than 50%. The present study demonstrates that NP causes oxidative stress by inhibiting superoxide dismutase activity and greatly affects the re-burrowing capability of T. philippinarum, even at environmentally realistic concentrations.

Evaluation of 4-nonylphenol toxicity in the clam Tapes philippinarum

Lethal and sublethal effects of 4-nonylphenol (NP) were investigated in the clam Tapes philippinarum from the Lagoon of Venice. In a 96-h lethality test, bivalves were exposed to the following NP concentrations: 0, 0+acetone, 0.19, 0.38, 0.75, 1.5, and 3.0mg NP/L. The 96-h LC(50) value was 1.12mg NP/L. No mortality was observed at 0.19mg NP/L, whereas at 1.5 and 3.0mg NP/L both siphons and foot of clams were often cut-off, the animals being unable to withdraw them before shell closure, suggesting the possible narcotic effect of NP. Lower concentrations (0, 0+acetone, 0.025, 0.05, 0.1, and 0.2mg NP/L) were then used to evaluate sublethal NP effects on clearance rate (CR), respiration rate (RR), scope for growth (SFG), and survival in air. Following a 7-day exposure, decreased RRs were found at all NP concentrations tested. Significant decreases in the CR and SFG were only observed at the two highest NP concentrations (0.1 and 0.2mg/L), with SFG reductions reaching 54% and 71%, respectively. Last, the highest concentrations tested significantly decreased the resistance of clams to exposure to air and enhanced the mortality rate. As the lowest effective NP concentrations are similar to environmentally realistic levels, a condition of potential risk for the well-being of clam populations in estuarine areas is highlighted.

Effects of copper and cadmium exposure on functional responses of hemocytes in the clam, Tapes philippinarum

The effects of Cu and Cd on functional responses of hemocytes in Tapes philippinarum, a Veneridae clam widespread in the lagoon of Venice, were evaluated. Bivalves were exposed for 7 days to various concentrations of CuCl(2) x 2H(2)O (0, 10, 60, and 110 microg/L) and CdCl(2) x H(2)O (0, 150, 300, and 450 microg/L). Hemocytes were collected from exposed clams, and the effects of Cu and Cd on phagocytosis, Neutral Red retention capacity, superoxide dismutase, and cytochrome oxidase activities were investigated. Hemocytes from animals exposed to Cu showed a significant decrease in phagocytic activity, whereas no inhibition was observed in cells from Cd-exposed animals. Diffusion of Neutral Red into the cytosol, an index of lysosomal membrane alteration, was enhanced by high concentrations of both metals. Different results in biochemical parameters were observed. Exposure to 60 and 110 microg Cu/L caused a significant reduction in hemocyte superoxide dismutase activity, whereas no changes resulted after Cd exposure. Increased cytochrome oxidase activity was observed in hemocytes from mollusks exposed to 60 microg Cu/L and 300 microg Cd/L; no significant differences were found in cells from bivalves exposed to 110 microg Cu/L and 450 microg Cd/L. These results suggest a relationship between heavy metal exposure and alterations in functional responses of hemocytes in T. philippinarum and indicate that the type of observed effects vary with the nature and concentration of heavy metals. Moreover, the data obtained in the analyzed clam support the possibility of using it as sentinel organism in biomonitoring studies, even if used biomarkers will be further evaluated in field conditions.

Haemocytes of the clam Tapes philippinarum (Adams & Reeve, 1850): morphofunctional characterisation

Tapes philippinarum is a bivalve mollusc of the Pacific Ocean, successfully imported for human consumption into the northern Adriatic Sea (Europe). For better knowledge of its considerable adaptive ability in comparison with similar autochthonous species, a morpho-functional characterisation of its haemocytes was carried out with the establishment of short-term cell cultures (60 min at 25 degrees C). Various methods of cytochemical staining identified four cell types in the haemolymph: granulocytes (48.05% +/- 1.43), hyalinocytes (32.18% +/- 0.99), haemoblasts (18.97% +/- 0.63) and serous cells (0.8% +/- 0.19). The granulocytes, possessing cytoplasmic granules with differing dye affinity, included basophils, neutrophils and acidophils. Such granules stained vitally with Neutral Red, and correspond to lysosomes. Hydrolytic and oxidative enzymes were mainly detectable after stimulation in the presence of yeast cells. Both granulocytes and hyalinocytes were positive for alkaline phosphatase, non-specific esterase, peroxidase, and cytochrome C oxidase, whereas only granulocytes were positive for beta-glucuronidase, acid esterase, and arylsulphatase. Both cell types were competent phagocytes towards yeast and plasma had an opsonising effect. Moreover, the respiratory burst accompanied phagocytosis with superoxide anion production, recognisable through cytoplasmic deposits of formazan after treatment with nitro blue tetrazolium. Haemoblasts were small undifferentiated cells which, due to their morphology and positivity to the anti-CD34 antibody, show the typical features of stem cells. Serous cells, probably arising from Keber's gland and belonging to another differentiation pathway, contained non-sulphate acid mucopolysaccharides and play an important role in early defence mechanisms, taking part in the formation of clots.

Immunotoxic effects of organotin compounds in Tapes philippinarum

One of the most harmful groups of coastal pollutants is the organotin compounds (OTCs) which have severe effects on both aquatic organisms and mammals including humans. The immunotoxic effects of OTCs were studied in the cultivated clam Tapes philippinarum by determining the immunosuppressant role on in vitro yeast phagocytosis at low doses (0.01, 0.05, 0.1 microM). The phagocytic index was significantly reduced in an irreversible non-lethal manner depending on concentration and lipophilic affinity. The order of inhibition was TBT > or = DBT > MBT for butyltins and TPTC > TPTA > or = TPTH for triphenyltins.

Prostatic UroLume Wallstent for benign prostatic hyperplasia patients at poor operative risk: clinical, uroflowmetric and ultrasonographic patterns

The prostatic UroLume Wallstent was positioned in 30 poor operative risk patients with bladder outlet obstruction due to benign prostatic hyperplasia. Preoperatively, 12 patients (40%) could still void spontaneously (group 1), while 18 (60%) had an indwelling catheter (group 2). Preoperative and postoperative assessment included scoring of subjective symptoms, physical examination, uroflowmetry with maximum flow nomogram, transrectal ultrasonography of the prostate, determination of residual urine volume and cystourethroscopy. All but 1 patient could void spontaneously after insertion of the stent. In group 1 preoperative and 1-year followup mean (plus or minus standard error) peak flow rates were 8.0 +/- 0.7 ml. per second and 15.8 +/- 1.8 ml. per second, respectively (p < 0.01), the mean residual urine volumes were 127 +/- 27 ml. and 38 +/- 11 ml. (p < 0.05), respectively, and the mean maximum flow nomograms (plus or minus standard deviation) were -2.6 +/- 0.1 and -1.4 +/- 0.4, respectively. In group 2 the 1-year followup mean peak flow rate, residual urine volume and maximum flow nomogram were 13.2 +/- 0.8 ml. per second (standard error), 32 +/- 14 ml. (standard error) and -1.5 +/- 0.1 (standard deviation), respectively. According to the maximum flow nomogram values all patients were nonobstructed postoperatively. At 1 year the stent was completely covered by prostatic epithelium in 90% of the patients, while in the remainder it was still partially visible at urethroscopy. Transrectal ultrasonography had an essential role in patient followup by accurately assessing the position of the stent. Placement of this prostatic stent is safe and effective for selected benign prostatic hyperplasia patients who cannot undergo surgical treatment due to poor operative risk.

Long-term clinical reliability of transurethral and open prostatectomy for benign prostatic obstruction: a term of comparison for nonsurgical procedures

To elucidate the long-term reliability of prostatectomy, we evaluated 92 benign prostatic hyperplasia patients who had been submitted to either transurethral or open surgery at the 5-year follow-up. Ninety-five percent of the patients were still nonobstructed and subjectively satisfied of their urinary status. Postoperative mortality was presumably not related to the previous operation. Until now, nonsurgical procedures did not guarantee the results achieved by surgical treatment and should thus be reserved for patients at high operative risk or refusing surgery.

Is there a role for transrectal microwave hyperthermia of the prostate in the treatment of abacterial prostatitis and prostatodynia?

Transrectal microwave hyperthermia of the prostate was administered to 54 patients with chronic abacterial prostatitis or prostatodynia, who failed to respond to several courses of conventional therapies. Hyperthermia was delivered in 60-min long sessions with three randomly chosen regimens (1 session/week for 4 weeks; 1 session/week for 6 weeks; 2 sessions/week for 3 weeks). A prostatic temperature of 42.5 +/- 0.5 degrees C was maintained throughout the entire duration of each session. Patients were assessed pre- and postoperatively by scoring of subjective symptoms, uroflowmetry with flow nomograms, determination of residual urine volume, and transrectal ultrasonography of the prostate. At the long-term follow-up, the subjective symptom score was significantly improved in all patients. Fifty percent of the patients also reported an improvement of life quality, 47% reported their condition unchanged, and 3% reported deterioration, despite therapy. Urodynamic parameters improved but did not reach statistical significance. No major complications were encountered. Our preliminary data indicate that transrectal microwave hyperthermia of the prostate is a safe therapy that can be beneficial as a second line treatment in selected patients with recurring symptoms of abacterial prostatitis or prostatodynia, which do not respond to medical therapy.

Transrectal microwave hyperthermia for benign prostatic hyperplasia: long-term clinical, pathological and ultrastructural patterns

Transrectal microwave hyperthermia of the prostate was administered to 191 patients with bladder outlet obstruction due to benign prostatic hyperplasia who were either at poor operative risk or who refused surgery. Patients were divided in 2 groups according to age and they underwent either 5 or 10, 60-minute sessions of hyperthermia, with a calculated intraprostatic temperature of 42.5 plus or minus 0.5C. Light and electron microscopy showed no irreversible damage at the glandular epithelium but did demonstrate a significant increase in neoformed intraprostatic capillary-like vessels. At 1, 12 and 24 months residual urine volume was significantly decreased in the majority of patients but only a minor amelioration of urinary flow rates and subjective symptoms was observed. According to maximum flow nomograms all patients were still obstructed postoperatively. Transrectal hyperthermia cannot be considered a genuine alternative to surgery for patients with bladder outlet obstruction due to benign prostatic hyperplasia.

Transrectal hyperthermia-induced histological and ultrastructural changes of human benign prostatic hyperplasia tissue

This prospective study evaluated the tissutal, cellular and intracellular effects of transrectal microwave hyperthermia on human benign prostatic hyperplasia. Forty-eight patients with benign prostatic hyperplasia underwent ten 60-min-long sessions of transrectal hyperthermia with an intraprostatic calculated temperature of 42 +/- 0.5 degrees C. Ultrasound-guided transperineal biopsies of the prostate were taken before and 1 month after completion of treatment. Postoperatively, morphometric analysis of bioptic specimens showed a statistically significant (p < 0.01) increase in the number of intraprostatic arterioles and capillary-like vessels. Diffused inflammatory infiltrates were also noted. Postoperative integrity of intracellular organelles and cellular membranes was evidenced by transmission electron microscopy. Our regimen of transrectal prostatic hyperthermia did not cause any irreversible histological or ultrastructural damage to the prostatic tissue. Hyperthermia-induced increase in blood flow could enhance drug delivery to the prostate gland.