Adverse respiratory patterns in near-term spontaneously breathing newborn lambs with elevated airway liquid volumes at birth.

Introduction: Recent evidence indicates that respiratory distress (RD) in near-term infants is caused by elevated airway liquid (EL) volume at the beginning of air-breathing after birth. While the adverse effects EL volumes on newborn lung function are known, the effects on respiratory control and breathing patterns shortly after birth (<4 h) are unknown. We investigated the effects of EL volumes on cardiorespiratory function and breathing patterns in spontaneously breathing near-term newborn lambs in the first hours after birth. Methods: At 137-8 days gestation (2-3 days prior to delivery; term ∼147 days), sterile surgery was performed on fetal sheep (n = 17) to implant catheters and blood flow probes. At 140 days, lambs were delivered via caesarean section under spinal anaesthesia. Airway liquid volumes were adjusted to mimic the level expected following vaginal delivery (∼10 ml/kg; Controls; n = 7), or elective caesarean section (∼30 ml/kg; elevated airway liquid group; EL; n = 10). Spontaneous breathing and cardiorespiratory parameters were recorded over four hours after birth. Non-invasive respiratory support with supplemental oxygen was provided if required. Results: EL lambs required higher inspired oxygen levels (p = 0.0002), were less active (p = 0.026), fed less (p = 0.008) and had higher respiratory morbidity scores than Controls (p < 0.0001). EL lambs also displayed higher rates of breathing patterns associated with RD, such as expiratory braking and tachypnoea. These patterns were particularly evident in male EL lambs who displayed higher levels of severe respiratory morbidity (e.g., expiratory braking) than female EL lambs. Conclusion: The study demonstrates that EL volumes at birth trigger respiratory behaviour and breathing patterns that resemble clinically recognised features of RD in term infants.

Respiratory patterns in spontaneously breathing near-term lambs delivered by caesarean section under spinal anaesthesia.

Introduction: The transition to newborn life has typically been studied in intubated and mechanically ventilated newborn lambs delivered via caesarean section (CS) under general anaesthesia. As a result, little is known of the spontaneous breathing patterns in lambs at birth, particularly those at risk of developing respiratory distress (RD). We have developed a method for delivering spontaneously breathing near-term lambs to characterise their breathing patterns in the immediate newborn period. Methods: At 137-8 days gestation (2-3 days prior to delivery; term ∼147 days), fetal lambs (n = 7) were partially exteriorised for instrumentation (insertion of catheters and flow probes) before they were returned to the uterus. At 140 days, lambs were delivered via CS under light maternal sedation and spinal anaesthesia. Lambs were physically stimulated and when continuous breathing was established, the umbilical cord was clamped. Breathing patterns were assessed by measuring intrapleural and upper-tracheal pressures during the first four hours after birth. Results: Newborn lambs display significant heterogeneity in respiratory patterns in the immediate newborn period that change with time after birth. Seven distinct breathing patterns were identified including: (i) quiet (tidal) breathing, (ii) breathing during active periods, (iii) breathing during oral feeding, (iv) tachypnoea, (v) expiratory braking manoeuvres, (vi) expiratory pauses or holding, and (vii) step changes in ventilation. Conclusions: We have described normal respiratory behaviour in newborn lambs, in order to identify respiratory behaviours that are indicative of RD in term newborn infants.

Assessing lung aeration using ultrasound after birth in near-term lambs at risk of respiratory distress.

Background: Optimizing respiratory support after birth requires real-time feedback on lung aeration. We hypothesized that lung ultrasound (LUS) can accurately monitor the extent and progression of lung aeration after birth and is closely associated with oxygenation. Methods: Near-term (140 days gestation, term ∼147 days), spontaneously breathing lambs with normal (controls; n = 10) or elevated lung liquid levels (EL; n= 9) were delivered by Caesarean section and monitored for four hours after birth. LUS (Phillips CX50, L3-12 transducer) images and arterial blood gases were taken every 5-20 min. LUS images were analyzed both qualitatively (grading) and quantitatively (using the coefficient of variation of pixel intensity (CoV) to estimate the degree of lung aeration), which was correlated with the oxygen exchange capacity of the lungs (Alveolar-arterial difference in oxygen; AaDO2). Results: Lung aeration, measured using LUS, and the AaDO2 improved over the first 4 h after birth. The increase in lung aeration measured using CoV of pixel intensity, but not LUS grade, was significantly reduced in EL lambs compared to controls (p = 0.02). The gradual decrease in AaDO2 after birth was significantly correlated with increased lung aeration in both control (grade, r2 = 0.60, p < 0.0001; CoV, r2 = 0.54, p < 0.0001) and EL lambs (grade, r2 = 0.51, p < 0.0001; CoV, r2 = 0.44, p < 0.0001). Conclusions: LUS can monitor lung aeration and liquid clearance after birth in spontaneously breathing near-term lambs. Image analysis techniques (CoV) may be able detect small to moderate differences in lung aeration in conditions with lung liquid retention which are not readily identified using qualitative LUS grading.

Using biological effects tools to define Good Environmental Status under the European Union Marine Strategy Framework Directive.

The use of biological effects tools offer enormous potential to meet the challenges outlined by the European Union Marine Strategy Framework Directive (MSFD) whereby Member States are required to develop a robust set of tools for defining 11 qualitative descriptors of Good Environmental Status (GES), such as demonstrating that "Concentrations of contaminants are at levels not giving rise to pollution effects" (GES Descriptor 8). This paper discusses the combined approach of monitoring chemical contaminant levels, along side biological effect measurements relating to the effect of pollutants, for undertaking assessments of GES across European marine regions. We outline the minimum standards that biological effects tools should meet if they are to be used for defining GES in relation to Descriptor 8 and describe the current international initiatives underway to develop assessment criteria for these biological effects techniques.

An assessment of salmon farms and wild salmonids as sources of Lepeophtheirus salmonis (Krøyer) copepodids in the water column in Loch Torridon, Scotland.

Wild salmonids and farmed salmon can both be sources of Lepeophtheirus salmonis (Krøyer, 1838) larvae. Farmed salmon smolts free of L. salmonis infections are stocked in sea cages and may subsequently contract L. salmonis infections, probably from wild fish. The contribution of gravid L. salmonis at Atlantic salmon, Salmo salar L., farms to populations of L. salmonis larvae in the water column has in the past been based on estimated parameters, such as louse fecundity. This present study augments these calculations by combining empirical data on densities of infective L. salmonis copepodids in the field with estimates of the number of gravid L. salmonis on farmed and wild salmonids in Loch Torridon. Data collected between 2002 and 2007 show a significant correlation between mean densities of L. salmonis copepodids recovered in the water column and the numbers of gravid L. salmonis at the local salmon farms. Generally, the farms with greatest numbers of salmon were observed to have stronger correlations with densities of copepodids in the water than the farms with fewer fish. The study suggests that louse management approaches, e.g. treatment trigger levels, need to take account of individual farm biomass, or numbers of fish. This study highlights the importance of control of L. salmonis on salmon farms for the co-existence of both wild salmonid populations and the aquaculture industry.

Spatial and temporal distribution of Lepeophtheirus salmonis (Krøyer) larvae in a sea loch containing Atlantic salmon, Salmo salar L., farms on the north-west coast of Scotland.

A plankton survey investigated spatial and temporal distributions of larval sea lice in a sea loch on the north-west coast of Scotland. Plankton tows were collected approximately weekly at two depths (0 and 5 m) at five sample stations over a 2-year period. The survey began in March 2002 when Atlantic salmon, Salmo salar L., farms in the study area stocked with fish and finished in March 2004, after farms completed harvesting. Over 90% of lice recovered were Lepeophtheirus salmonis (Krøyer); therefore, the results of this paper refer largely to that species. The data were analysed using generalized additive models with explanatory variables for time, depth and station. Greatest densities of nauplii were recovered at stations adjacent to farms indicating that the local salmon farms were a likely source of larvae at times during the production cycle. There were significant temporal trends in larval densities and the stocking and harvesting of farms can possibly account for these increases and decreases, particularly at the start and at the end of the production cycle. The distribution of copepodids was more widespread than that of nauplii, indicating that the larvae can be transported several kilometres from the point of release.

Sediment influence on congener-specific PCB bioaccumulation by Mytilus edulis: a case study from an intertidal hot spot, Clyde Estuary, UK.

An intertidal site in the Clyde Estuary, UK, was selected to evaluate the role of sediment geochemistry on the bioaccumulation of polychlorinated biphenyls (PCBs) by mussels (Mytilus edulis). The area had previously been identified as showing anomalously high levels of PCB contamination (over 1,500 microg kg(-1) total PCB in sediment, 22 congeners). Samples of surface sediment and M. edulis were collected from two closely located sites, one within the anomalous area and another representing typical PCB contamination in the estuary. Sediment samples were separated into grain size fractions and analysed for a range of biomarker compounds, PCBs and sediment mineralogy. The anomalous site showed an atypical association of PCBs with sediment properties, despite both locations showing influence of both petrogenic and pyrogenic organic contamination. Interrogation of data using correlation and principal component analysis showed that sediment mineralogy as well as organic matter composition influenced PCB congener distribution. One sediment source was found to control the PCB concentration in mussels at both locations and clay mineralogy appears to control PCB uptake by biota with preference for higher molecular weight congeners. Overall bioavailability is determined by sediment TOC.

Application of SSH and a macroarray to investigate altered gene expression in Mytilus edulis in response to exposure to benzo[a]pyrene.

The lack of genomic resources for aquatic invertebrates restricts their use as sentinel species in coastal environments. It is known that where genomic data are not available, suppression subtractive hybridisation (SSH) can generate cDNA libraries representative of pollutant-responsive gene transcription in aquatic vertebrates. To assess whether the approach was equally suited to aquatic invertebrates, altered gene expression in digestive gland of the mussel, Mytilus edulis, in response to exposure to benzo[a]pyrene (BaP) (1 mg/l) was investigated with SSH and a nylon macroarray. Screening of the subtracted libraries showed 112/250 up-regulated and 25/55 down-regulated clones were positive for differential expression and characterisation of these identified 87 with unique sequence suitable for array on a nylon membrane. The transcripts isolated were from a diverse range of genes involved in general stress, oxidative stress, cell adhesion, transcriptional and translational regulation, transport mechanisms, energy metabolism, cell metabolism, lipid metabolism, protein turnover and activation, lysosomal activity and 22 cryptic clones. Subsequent use of the clones in macroarray format to analyse expression of BaP-responsive genes (0 vs 4 day exposed) showed 0-100-fold increased levels of the forward-subtracted probes and between 0 and 0.1-fold down-regulation of the reverse-subtracted probes. Only 15% of the clones showed less than 2-fold change in expression. The gene ontology of the transcripts isolated demonstrates that BaP elicits a multitude of responses with a major feature being disruption of cellular redox status. The results indicate that the use of SSH and a macroarray is a robust method to discover novel pollutant-responsive genes in aquatic invertebrates.

Implications from a field study regarding the relationship between polycyclic aromatic hydrocarbons and glutathione S-transferase activity in mussels.

An aluminium smelter on the west coast of Scotland discharges an aqueous effluent containing polycyclic aromatic hydrocarbons (PAHs) at the head of Loch Leven. The loch also supports two mussel (Mytilus edulis) farms. Data are presented on burdens of PAHs in the soft tissues of mussels and the effect of these contaminants on glutathione S-transferase (GST) activity in mussel hepatopancreas. GST activity is shown to be correlated with total PAH burden and also with the concentrations of certain individual PAHs. These field data show that high molecular weight PAHs are closely correlated to GST activity, whereas low molecular weight PAHs are not. This suggests that 5- and 6-ring PAHs have a more pronounced role than 2- to 4-ring compounds in inducing GST activity in mussels from Loch Leven. It is proposed that it may be more appropriate to link GST activity with 5- and 6-ring compounds only, rather than with the total PAH burden.

Biliary PAH metabolites and EROD activity in flounder (Platichthys flesus) from a contaminated estuarine environment.

The present study in the Firth of Forth, Scotland, emphasises the usefulness of biliary metabolite measurements in estuarine monitoring using the flounder (Platichthys flesus). The short time scale (a few hours) of response to polycyclic aromatic hydrocarbon (PAH) exposure, allowed clearer interpretation of trends and differences between sites. Such differences and trends in the metabolite data were not as apparent from 7-ethoxyresorufin O-deethlyation (EROD) activity measurements, which were likely to have been blurred by the movements of flounder between sites. Statistical differences were not observed in EROD activity in flounder from the Firth of Forth (ANOVA, P = 0.065). The biliary metabolites showed statistical differences between the uppermost site of Longannet and Port Edgar, in the outer Firth, for both the 1-OH pyrene and 2-OH naphthalene metabolites (ANOVA, Tukeys, P = 0.012 and 0.022 respectively). There was also a significant correlation between the concentrations of all three individual metabolites (1-OH pyrene, 2-OH naphthalene, I-OH phenanthrene) and the log of the distance downstream from the major PAH input sources of Longannet power station and Grangemouth. Biliary PAH metabolites were shown to better reflect local contamination gradients than EROD activity. This is explained by the relative response times of the two biomarkers and local movements of the flounder in the estuary.

Effect of cardiopulmonary bypass on pulmonary gas exchange: a prospective randomized study.

BACKGROUND: Conventional coronary artery bypass surgery is associated with postoperative pulmonary dysfunction. Inflammation due to cardiopulmonary bypass has been regarded as one of the main causes. In this study, we investigated the effect of coronary revascularization with or without cardiopulmonary bypass on pulmonary function. METHODS: Fifty-two patients (40 male, mean age 60.1 years) were prospectively randomized to undergo coronary revascularization via median sternotomy, with or without normothermic cardiopulmonary bypass. Alveolar-arterial oxygen gradients were measured before and after induction of anesthesia, postoperatively in the intensive care unit during mechanical ventilation and 6 hours after tracheal extubation. The techniques of anesthesia and mechanical ventilation were standardized throughout. RESULTS: Patient characteristics were similar in the two groups. The alveolar-arterial oxygen gradients increased progressively throughout the perioperative period, with no significant differences in the two groups at any time during the study. CONCLUSIONS: Myocardial revascularization with or without cardiopulmonary bypass caused a similar degree of pulmonary dysfunction, as assessed by alveolar-arterial oxygen gradient. Our study suggests that the deterioration in pulmonary gas exchange associated with cardiac surgery is due to factors other than the use of cardiopulmonary bypass.

A field evaluation of international monitoring guidelines for the biological effects of tributyltin.

The Oslo and Paris Commission (OSPAR) Guidelines for monitoring the biological effects of tributyltin compounds (TBT) were evaluated using data collected for preparation of a Celtic Seas Quality Status Report. Two types of survey were undertaken: broad scale, to determine wide impacts in coastal waters; and localised, around representative harbours to establish ranges of effect from recognised input points. This evaluation indicates that results from the broad scale surveys can be used to compare different areas of coastline. Nucella is widespread away from point sources although many individuals show some degree of imposex. Populations are generally not at risk. The localised surveys indicate that, in certain situations, the monitoring objectives can be met in the OSPAR Guidelines (subject to minor amendment). Criteria are identified for the selection of point sources suitable for monitoring under OSPAR Guidelines.

Kinetics of the development of imposex in transplanted adult dogwhelks, Nucella lapillus.

The degree of imposex in dogwhelks, Nucella lapillus (L.), is normally described in terms of a series of vas deferens development stages. The progression of adult female dogwhelks through vas deferens stages 0-5 in response to exposure to tributyltin at 2-128 ng/l has been modelled on the basis of first-order kinetics. Modelling indicated that the half-lives of stages 0, 1 and 2 were from 1-8 weeks and that the half-life of stage 3 was approximately twice as long. The half-life of stage 4 was 90-120 weeks. Half-lives decreased with increasing exposure concentration. The implications of these data for field surveys and transplantation experiments are discussed. Transplanted dogwhelks will not rapidly attain equilibrium with environmental conditions. Experiments will require careful control of exposure period, and preferable supporting chemical data.

Determination of (mono-, di- and) tributyltin in sediments. Analytical methods.

Methods for the reliable determination of butyltin compounds in sediments are required for both national and international marine monitoring programmes. This evaluation of current commonly used approaches to the analysis identifies critical aspects of extraction, derivatisation, clean-up, separation, standardisation and detection with the objective of improving the analytical capabilities both of experienced laboratories and of those addressing the problems for the first time.

Effect of freezing on the length of the penis in Nucella lapillus (L.).

When quantifying imposex in Nucella lapillus, two indices are used: the Vas Deferens Sequence Index (VDSI) and the Relative Penis Size Index (RPSI). Freezing and thawing increase the length of the penis in both male and female Nucella lapillus. In the population studied, this had no significant effect on the RPSI, but was potentially an important source of additional variance in the estimation of the mean penis length.

QUASIMEME laboratory performance study of the biological effects of tributyltin (imposex and intersex) on two marine gastropod molluscs.

The disruption of the endocrine systems of gastropod molluscs and consequential physiological changes (imposex and intersex) are used as biomarkers for environmental contamination by tributyltin compounds. The first international laboratory performance study on the determination of imposex and intersex in neogastropod molluscs, Nucella lapillus and Littorina littorea has been undertaken by the QUASIMEME (Quality Assurance of Information for Marine Environmental Monitoring in Europe) project. Samples of live gastropods were distributed and participants were asked to record shell height and sex, together with penis length and vas deferens sequence stage (VDS) in Nucella or the intersex stage (IS) and prostate length in Littorina. Calculations were made of vas deferens sequence index (VDSI) and the relative penis size index (RPSI) in Nucella and of intersex stage index (ISI) and the average female prostate length (FPrL) in Littorina. Thirteen (87%) of the 15 participating laboratories returned data. The remaining two laboratories asked to participate in later exercises. For Nucella, seven laboratories reported sex ratios significantly different from the reference laboratory data. Differences in penis length measurements between laboratories were largely random, although there were indications of systematic errors affecting the data from three laboratories. Seven laboratories reported satisfactory data (Z-score magnitude of Z < 2) for VDSI. The inclusion of a high proportion of sub-adults in the Nucella samples may have made separation of the sexes more difficult than in mature adults. The sub-adults will have had smaller pene than mature adults in the same population, and therefore any errors (random or systematic) in the measurement of penis length or observation of reproductive organs would have a potentially greater impact on the final reported values of the summary imposex indices. The Littorina sample did not show a high degree of intersex (ISI = 0.41). The laboratories could determine the sex of Littorina reliably and only one laboratory reported data significantly different from the reference laboratory. All except two laboratories reported satisfactory data for ISI.

Imposex measurement in the dogwhelk Nucella lapillus (L.)--temporal aspects of specimen preparation.

The measurement of the Relative Penis Size Index (RPSI) in the dogwhelk Nucella lapillus (L.) depends upon reliable observations of the length of the penis (PL). Following removal of soft tissue from the shell, PL increases with time leading to a progressively greater over-estimation of the RPSI. The error is proportionally greater at low RPSI values. To retain comparability with previous data, it is suggested that dogwhelks should be examined as soon as possible after shell crushing.

Tributyltin contamination in the Firth of Forth (1975-87).

Contamination of the Firth of Forth (Scotland) by tributyltin compounds leached from antifouling paints has been identified using the degree of penis development (imposex) in the common dogwhelk Nucella lapillus. In 1987, a high degree of imposex was observed in the vicinity of pleasure craft activity, fishing harbours and a boat yard, reflecting localised inputs of tributyltin from these sources. Dogwhelks collected in 1975 from sites comparable to those surveyed in 1987 showed lower degrees of imposex and also a lower incidence of penis development in females.