The effects of oil exploration and production in the Fladen Ground: composition and concentration of hydrocarbons in sediment samples collected during 2001 and their comparison with sediment samples collected in 1989

Due to the potentially accumulative nature of the Fladen Ground, an area of intense oil activity in the North Sea, a survey was carried out in 1989 to map the distribution of contamination in relation to these oil activities. All the sediments collected were screened by ultraviolet fluorescence (UVF) for polycyclic aromatic hydrocarbons (PAHs) and selected samples were analysed for n-alkanes (by GC-FID), PAHs and biomarkers (by GC-MSD). This survey was repeated in 2001, with all the 1989 sites being resampled. All of these sediments were analysed for UVF oil equivalents, PAHs, n-alkanes and biomarkers. The concentrations of these parameters decreased between 1989 and 2001, with average decreases ranging from 43% to 88%. In addition, no significant difference was found, for all the parameters, between near field (<5 km from an oil installation) and far field (>5 km from an oil installation) sites in 2001 indicating that the Fladen Ground is approaching a 'steady state' or background concentration for contamination.

Polycyclic aromatic hydrocarbon (PAH) concentration and composition determined in farmed blue mussels (Mytilus edulis) in a sea loch pre- and post-closure of an aluminium smelter

Concentrations of polycyclic aromatic hydrocarbons (2- to 6-ring parent and branched PAH) from an actively producing commercial shellfish farm in Loch Leven, Scotland, were found in excess of 4000 ng g(-1) wet weight tissue. These concentrations were considerably greater than had been recorded from mussels sampled elsewhere around the Scottish mainland. The PAH composition of the mussels from Loch Leven was dominated by the 5-ring, parent compounds; benzo[b]fluoranthene was the dominant compound. This data was consistent with the source being a discharge from an aluminium smelter. The individual compounds benz[a]anthracene, benzo[a]pyrene and dibenz[a,h]anthracene returned values of 304 ng g(-1), 446 ng g(-1) and 39 ng g(-1) respectively; these were well above the 15 ng g(-1) pragmatic guideline limit. Over the two year monitoring period, the concentrations of these compounds in mussels from Loch Etive, a reference location, ranged between 'not detected' and 4 ng g(-1)(for benz[a]anthracene). Mussels were transferred from a clean location to Loch Leven which demonstrated that the rate of uptake of PAH was rapid. Following closure of the aluminium smelter, the PAH concentrations in mussels decreased. Differences between the two sites within Loch Leven were noted with the longer-term impact remaining greater for the mussels closer to the original point discharge.

The polycyclic aromatic hydrocarbon and geochemical biomarker composition of sediments from sea lochs on the west coast of Scotland

Sediments from twelve sea lochs on the west coast of Scotland were analysed for parent and branched 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs), n-alkanes and geochemical biomarkers (triterpanes). Where possible at least fourteen sediment samples were collected at random from each sea loch. All sea lochs were remote, most had limited industrial and urban inputs, although all had fish farms. Four lochs had moderate total PAH concentrations and eight lochs had high total PAH concentrations. Total PAH concentration was related to organic carbon content and particle size distribution, with sandier sediments having lower PAH concentrations. The highest total PAH concentrations, normalised for organic carbon, were in Loch Linnhe and Ballachulish Bay (Loch Leven), close to an aluminium smelter. PAH concentration ratios showed that pyrolysis was the main source of PAHs in most lochs. Only sediments from Loch Clash showed evidence of petrogenic input based on their geochemical biomarker (triterpane and sterane) and n-alkane profiles. PAH profiles were similar across lochs apart from Loch Linnhe and Ballachulish Bay, which had a greater proportion of heavy parent PAHs. West coast sediments had a smaller proportion of heavy PAHs than sediments collected from voes in Shetland and a smaller proportion of alkylated PAHs relative to sediments collected from coastal waters around Orkney.

Out of Anatolia: longitudinal gradients in genetic diversity support an eastern origin for a circum-Mediterranean oak gallwasp Andricus quercustozae

Many studies have addressed the latitudinal gradients in intraspecific genetic diversity of European taxa generated during postglacial range expansion from southern refugia. Although Asia Minor is known to be a centre of diversity for many taxa, relatively few studies have considered its potential role as a Pleistocene refugium or a potential source for more ancient westward range expansion into Europe. Here we address these issues for an oak gallwasp, Andricus quercustozae (Hymenoptera: Cynipidae), whose distribution extends from Morocco along the northern coast of the Mediterranean through Turkey to Iran. We use sequence data for a fragment of the mitochondrial gene cytochrome b and allele frequency data for 12 polymorphic allozyme loci to answer the following questions: (1). which regions represent current centres of genetic diversity for A. quercustozae? Do eastern populations represent one refuge or several discrete glacial refugia? (2). Can we infer the timescale and sequence of the colonization processes linking current centres of diversity? Our results suggest that A. quercustozae was present in five distinct refugia (Iberia, Italy, the Balkans, southwestern Turkey and northeastern Turkey) with recent genetic exchange between Italy and Hungary. Genetic diversity is greatest in the Turkish refugia, suggesting that European populations are either (a). derived from Asia Minor, or (b). subject to more frequent population bottlenecks. Although Iberian populations show the lowest diversity for putatively selectively neutral markers, they have colonized a new oak host and represent a genetically and biologically discrete entity within the species.

The polycyclic aromatic hydrocarbon composition of mussels (Mytilus edulis) from Scottish coastal waters

Blue mussels (Mytilus edulis) were collected from coastal areas and voes in Shetland and Orkney during March and April 1998 and from various coastal locations around mainland Scotland and from the Islands during October and December 1999. The polycyclic aromatic hydrocarbon concentration and composition (2- to 6-ring parent and branched) were determined for all samples. Additional analysis, including sensory assessment and the determination of n-alkanes and geochemical biomarkers, was also undertaken on the Shetland and Orkney mussels collected in 1998. Mussels from Shetland and Orkney exhibited a wide range of total PAH concentration (14.7 to 7,177 ng g(-1) wet weight). Those mussels collected in 1999 exhibited a narrower concentration range. The lowest value (mussels from Loch Kentra) was 8.4 ng g(-1) wet weight while the maximum concentration was 344.1 ng g(-1) wet weight and was determined in mussels from Granton East in the Firth of Forth. The PAH concentration ratios in mussels from Dury Voe (Grunna), Long Hope and Kirkwall Bay were consistent with a predominately petrogenic source for these contaminants. This was supported by both the sensory assessment and the n-alkane and triterpane profiles. Comparisons of the PAH concentrations in mussels with sediments collected from the same locations around Shetland and Orkney showed that in areas of high sediment PAH concentration the bioavailability of these contaminants was limited.

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.

Different levels of mussel (Mytilus edulis) DNA strand breaks following chronic field and acute laboratory exposure to polycyclic aromatic hydrocarbons

Levels of polycyclic aromatic hydrocarbons (PAHs) including benzo[a]pyrene (B[a]P) were at least seven-fold higher in mussels sampled from a polluted site (Loch Leven, in Scotland, UK) compared to a nearby clean reference site (Loch Etive) throughout the year 2000. Levels of DNA strand breaks (alkaline COMET assay) using both gill and digestive gland nuclei were similar at both sites despite the difference in contaminant load (total PAH). In contrast, mussels collected from a reference site (Port Quin, Cornwall, UK) had an increase in DNA strand breaks in digestive gland cells following laboratory exposure to B[a]P-dosed Isochrysis galbana. However, after 14 days high dose (20 ppb-exposed diet) animals had returned to levels similar to the controls. There was no evidence of increased necrosis or apoptosis after treatments. The results from these two studies suggest that an adaptive response may prevent ongoing DNA damage in mussels exposed to high levels of B[a]P and PAH contamination.

Chlorobiphenyl contaminants at Pladda and Garroch Head in the Firth of Clyde following the cessation of sewage sludge dumping

Sewage sludge dumping at Garroch Head in the Firth of Clyde ceased on 31 December 1998. Eighteen of the 209 chlorinated biphenyls (CBs) were measured in plaice livers, collected in 1999 and 2000, from the former Garroch Head dump site. Samples were also obtained from Pladda, a site reasonably remote from the former dump site but also in the Clyde, in 1999 only. These results were compared to the CB concentrations in plaice livers collected between 1992 and 1998 from Garroch Head and Pladda. Additional samples were also taken from a clean reference site, close to Colonsay. Concentrations of the congeners in the livers of fish caught at the former Garroch Head dump site in 1999 were marginally higher than those from Pladda, with a mean CB concentration of 1861 microg kg(-1) lipid in the Garroch Head plaice livers and 1725 microg kg(-1) lipid for the sample from Pladda. The mean CB concentration in the 2000 Garroch Head samples was 2253 microg kg(-1) lipid. CB concentration in plaice livers from Colonsay were lower than both the Pladda and Garroch Head fish, with plaice livers from Colonsay giving a mean CB concentration of 1076 microg kg(-1) lipid in 1999 and 345.1 microg kg(-1) lipid in 2000. The data was evaluated using principal component analysis (PCA). Pattern analysis was undertaken by normalising to the recalcitrant CB 153. There was an indication that the CB pattern has changed since the cessation of dumping with the proportion of tri- and tetra-chlorinated CBs being lower in plaice from Garroch Head than in previous years.

The polycyclic aromatic hydrocarbon and geochemical biomarker composition of sediments from voes and coastal areas in the Shetland and Orkney Islands

Marine sediments from coastal areas and voes in the Shetland and Orkney Islands were analysed for parent and branched 2- to 6-ring polycyclic aromatic hydrocarbons (PAHs) and geochemical biomarkers. Where possible 14 sediment samples were collected at random from each of 17 Shetland and 9 Orkney sites. The wide range of total PAH concentrations in sediments (i.e., < LOD up to 22619 ng g(-1) dry weight) was indicative of a variety of anthropogenic activities and different sediment types associated with the specific locations. Low PAH concentrations were determined in sandy sediments from areas of limited boat activity. The highest PAH concentrations were found in muddy sediment close to a boat repair yard. PAH concentration ratios were consistent with the main source of these compounds, in most areas, being pyrolysis. Geochemical biomarker (triterpane and sterane) profiles from the sediment were indicative, for some areas, of limited petrogenic input. Punds Voe was the only voe to show evidence of North Sea oil. PAH profiles were similar across sites within each island group, with any differences attributable to known local sources of PAHs. However, there was a clear difference in the PAH profiles of Shetland and Orkney sediments, with Orkney sediments having a higher proportion of the lighter alkylated PAHs.

Event-related potential evidence for age-related differences in attentional allocation during a source monitoring task

Event-related potentials (ERPs) were recorded while older and younger adults were engaged in a source monitoring task. After studying a list of words, participants were presented with a recognition test during which some of the new words were repeated, rendering them as familiar as the study words. Instructions at test indicated whether the goal was to select the previously studied words or the repeated test items. Behaviorally, the younger adults were less likely to make source monitoring errors. ERPs, averaged only for correct trials, indicated that younger adults produced late positivities of greatest amplitude in response to whichever word type was designated as target irrespective of its familiarity. The ERPs of the older adults were generally less differentiated and their late positivities greater for recently repeated words irrespective of target designation. These results suggest that source monitoring in young adults is facilitated by their ability to allocate and withdraw attention from stimuli on the basis of task relevance rather than familiarity alone, and that this attentional flexibility declines with age.

A phase I study of paclitaxel and altretamine as second-line therapy to cisplatin regimens for ovarian cancer

PURPOSE

The efficacy and pharmacokinetics of paclitaxel when combined with altretamine for ovarian cancer were studied.

METHODS

A group of 30 patients, whose only chemotherapy was one or more cisplatin-based non-paclitaxel-containing regimens and whose ovarian cancer failed to respond or had relapsed within 6 months of their last platinum regimen, received paclitaxel as a 3-h intravenous infusion and altretamine given orally in four divided doses daily for 14 days repeated every 28 days. Doses were escalated from paclitaxel/altretamine 135/150 mg/m2 to 250/300 mg/m2 in cohorts of three patients.

RESULTS

The dose-limiting toxicities at 250/300 mg/m2 were WHO grade 3 myalgias and arthralgias in two patients and grade 3 lethargy, stomach cramps, peripheral neuropathy and vomiting in single patients. Considering all dose levels in cycle 1, 16 patients had grade 3 or 4 neutropenia but there was only one episode of febrile neutropenia. Other grade 3 toxicities were vomiting in four patients, myalgias in three, peripheral neuropathy in two and lethargy in two. Grade 3 alopecia occurred in 23 patients. Three patients achieved a complete response and 12 achieved a partial response for an overall objective response rate of 50%. Responses occurred at all dose levels of 175/150 mg/m2 and higher. The median freedom from progression was 35 weeks, with a median survival of 55 weeks. Altretamine did not alter the pharmacokinetics of paclitaxel and there were no consistent differences in paclitaxel pharmacokinetic parameters or toxicities between course 1 and 2. No dose-response relationships were evident above paclitaxel/altretamine 175/150 mg/m2.

CONCLUSION

Paclitaxel and altretamine can be safely combined and with a high response rate in relapsed ovarian cancer, justifying further studies with this combination.

Identification of gene expression profiles that predict the aggressive behavior of breast cancer cells

With the goal of identifying genes that have an expression pattern that can facilitate the diagnosis of primary breast cancers (BCs) as well as the discovery of novel drug leads for BC treatment, we used cDNA hybridization arrays to analyze the gene expression profiles (GEPs) of nine weakly invasive and four highly invasive BC cell lines. Differences in gene expression between weakly and highly invasive BC cells were identified that enabled the definition of consensus GEPs for each invasive phenotype. To determine whether the consensus GEPs, comprising 24 genes, could be used to predict the aggressiveness of previously uncharacterized cells, gene expression levels and comparative invasive and migratory characteristics of nine additional human mammary epithelial cell strains/lines were determined. The results demonstrated that the GEP of a cell line is predictive of its invasive and migratory behavior, as manifest by the morphology of its colonies when cultured on a matrix of basement membrane constituents (i.e., Matrigel). We found that the expression of keratin 19 was consistently elevated in the less aggressive BC cell lines and that vimentin and fos-related antigen-1 (FRA-1) were consistently overexpressed in the more highly aggressive BC cells. Moreover, even without these three genes, the GEP of a cell line still accurately predicted the aggressiveness of the BC cell, indicating that the expression pattern of multiple genes may be used as BC prognosticators because single markers often fail to be predictive in clinical specimens.

Soluble TNF receptors in vitreoretinal proliferative disease

PURPOSE

To measure vitreous levels of soluble TNF-receptors (sTNF-Rs) types I and II in eyes with rhegmatogenous retinal detachment (RRD), uncomplicated or complicated with proliferative vitreoretinopathy (PVR), and in eyes with proliferative diabetic retinopathy (PDR). To examine whether there is any relationship between vitreous levels of sTNF-Rs and clinical features of these conditions and between vitreous sTNF-Rs and TNFalpha levels and serum levels of sTNF-RS:

METHODS

Vitreous levels of sTNF-Rs and TNFalpha were measured by enzyme-linked immunosorbent assay in 30 eyes with PVR, 30 eyes with uncomplicated RRD, and 29 eyes with PDR. Vitreous from eyes of 10 deceased donors and 9 eyes with macular holes served as control specimens. Serum levels of sTNF-Rs were measured in 17 patients with PDR and 21 patients with PVR.

RESULTS

Vitreous levels of sTNF-Rs I and II were increased in eyes with PVR, RRD, and PDR when compared with control eyes (P < 0.002). However, vitreous levels of sTNF-Rs I and II were higher in eyes with PVR than in eyes with RRD (P < 0.01) or PDR (P < 0.03). This contrasted with the findings that serum sTNF-Rs were higher in PDR than in PVR (P < 0.016) and that vitreous levels of TNFalpha were higher in eyes with PDR than in eyes with PVR (P < 0.0005). In PVR, vitreous sTNF-Rs levels were associated with the duration of retinal detachment, number of previous external operations, and grade of severity, whereas in PDR these levels were not related to the type or duration of diabetes or its complication with traction retinal detachment.

CONCLUSIONS

These observations suggest the existence of TNF inhibitory mechanisms within the eye during retinal processes of inflammation and angiogenesis. That high vitreous levels of sTNF-Rs relate to severity of retinopathy suggests that these molecules may constitute reactive products of inflammation. Effective control of TNFalpha activity by sTNF-Rs within the retinal microenvironment may determine the outcome and severity of retinal proliferative conditions.

Chlorobiphenyl contaminants at Pladda and Garroch Head in the Firth of Clyde in relation to sewage sludge input

Sewage sludge dumped at Garroch Head in the Firth of Clyde contains significant quantities of chlorinated hydrocarbons, such as polychlorinated biphenyls (CBs). These compounds are lipophilic and resistant to degradation. They accumulate in the biota either from the water column or through the food chain, particularly in tissue with a high lipid content. Bottom dwelling fish, such as plaice, in the vicinity of the dump site will accumulate CBs from their environment. Eighteen of the 209 CBs were measured in plaice livers from the Garroch Head dump site and from Pladda, a site reasonably remote from the dump site but also in the Clyde, over a 7 year period prior to the cessation of dumping in December 1998. Concentrations of the congeners in the liver of fish caught at the dump site were, in general, higher than those in the liver of fish caught at Pladda. Concentrations in the plaice livers for the sum of 18 CBs ranged from 1611 to 8471 micrograms kg-1 lipid for Garroch Head samples and from 336.9 to 2635 micrograms kg-1 lipid for samples from Pladda. The data were evaluated using principal component analysis (PCA). Pattern analysis was undertaken by normalising to the recalcitrant CB 153. Livers from the dump site were found to have a higher proportion of the lower chlorinated CBs. CB patterns were similar at the Garroch Head dump site from year to year, but multivariate techniques showed that there were differences in pattern when normalised to CB 153.

Matrix metalloproteinases and their natural inhibitors in fibrovascular membranes of proliferative diabetic retinopathy

AIM

To examine epiretinal membranes of proliferative diabetic retinopathy (PDR) for the presence of selective matrix metalloproteinases (MMPs) and their natural inhibitors (TIMPs), in order to determine whether neovascularisation and fibrosis, characteristic of this complication of diabetes mellitus, are associated with specific anomalies of MMP or TIMP expression.

METHODS

The presence of selected MMPs and TIMPs was investigated in 24 fibrovascular epiretinal membranes of PDR, and the findings compared with that observed in 21 avascular epiretinal membranes of proliferative vitreoretinopathy (PVR) and five normal retinas. Specimens were examined for deposition of interstitial collagenase (MMP-1), stromelysin-1 (MMP-3), gelatinase A (MMP-2), gelatinase B (MMP-9), and three tissue inhibitors of metalloproteinases (TIMP-1, TIMP-2, and TIMP-3).

RESULTS

The results showed that unlike normal retina, which constitutively expresses MMP-1 and TIMP-2, a large proportion of PDR membranes (> 62%) stained for MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2, and TIMP-3. There were no differences in the expression of these molecules when compared with PVR membranes. A characteristic staining for MMP-9 was observed within the perivascular matrix of PDR membranes, and there was a significant increase in TIMP-2 expression by PDR membranes (p= 0.036) when compared with PVR membranes.

CONCLUSIONS

The findings that MMPs involved in degradation of fibrovascular tissue matrix, as well as TIMP-1 and TIMP-2, are found in a large proportion of PDR membranes, and that their expression does not differ from that of PVR membranes, suggest the existence of common pathways of extracellular matrix degradation in pathological processes leading to retinal neovascularisation and fibrosis.

Repair in the rabbit outflow system

An in vivo study was conducted to study repair processes in the injured rabbit outflow system. A uniform injury was produced by raising intraocular pressure (IOP) manometrically to 70 mmHg for 1 h. The recovery process, which was followed clinically for 8 weeks and morphologically for 6 weeks, led to the re-establishment of normal meshwork architecture within this period. The morphological studies included light microscopy, autoradiography and electron microscopy. The initial lesion consisted of large deficits in the meshwork with breakdown of cell-to-cell connections, loss of extracellular materials and disruption of the vessels of the aqueous plexus. There was a significant lowering of IOP in the first week of recovery, which thereafter climbed back to normal. Also in the first week the meshwork became infiltrated with inflammatory cells which cleared by 4 weeks. There was some meshwork cell death by either necrosis or apoptosis. The majority of meshwork cells became activated within the first few days and remained activated for at least the first 2 weeks. Tritiated proline incorporation was maximal between 1 and 2 weeks. Tritiated thymidine labelling was seen throughout, but only after the inflammation subsided was it clear that meshwork cells in all regions of the meshwork were proliferating. Our study provided no evidence that normal meshwork cells have a basal proliferative turnover level. Our injury model involved complete repair of the outflow tissues and that required meshwork cells to become activated, mobilise, undertake synthetic activity and proliferate. This is the first example, other than argon laser trabeculoplasty, where meshwork cells in vivo have been induced to divide. Possible therapeutic implications for glaucoma are discussed.

Identification of selective estrogen receptor modulators by their gene expression fingerprints

Clinical studies have shown that estrogen replacement therapy (ERT) reduces the incidence and severity of osteoporosis and cardiovascular disease in postmenopausal women. However, long term estrogen treatment also increases the risk of endometrial and breast cancer. The selective estrogen receptor (ER) modulators (SERMs) tamoxifen and raloxifene, cause antagonistic and agonistic responses when bound to the ER. Their predominantly antagonistic actions in the mammary gland form the rationale for their therapeutic utility in estrogen-responsive breast cancer, while their agonistic estrogen-like effects in bone and the cardiovascular system make them candidates for ERT regimens. Of these two SERMs, raloxifene is preferred because it has markedly less uterine-stimulatory activity than either estrogen or tamoxifen. To identify additional SERMs, a method to classify compounds based on differential gene expression modulation was developed. By analysis of 24 different combinations of genes and cells, a selected set of assays that permitted discrimination between estrogen, tamoxifen, raloxifene, and the pure ER antagonist ICI164384 was generated. This assay panel was employed to measure the activity of 38 compounds, and the gene expression fingerprints (GEFs) obtained for each compound were used to classify all compounds into eight groups. The compound's GEF predicted its uterine-stimulatory activity. One group of compounds was evaluated for activity in attenuating bone loss in ovariectomized rats. Most compounds with similar GEFs had similar in vivo activities, thereby suggesting that GEF-based screens could be useful in predicting a compound's in vivo pharmacological profile.

Analysis of sediments from Shetland Island voes for polycyclic aromatic hydrocarbons, steranes and triterpanes

A few days after the grounding of the oil tanker Braer on 5 January 1993, an Exclusion Zone was designated by Order under the Food and Environment Protection Act 1985, prohibiting the harvesting of farmed or wild shellfish within the Zone to prevent contaminated products reaching the market place. The order was progressively lifted for species that were found to be free of petrogenic taint and for which the polycyclic aromatic hydrocarbon (PAH) levels were within the range for reference samples. This Order, however, still remains in place for mussels (Mytilus edulis) as the PAH levels are higher than in reference mussels. To investigate the possible source of PAHs found in these mussels, sediments were collected from three reference and three Zone sites and their hydrocarbon compositions studied using the n-alkane composition and concentration, PAH composition and concentration and the sterane and triterpane composition. The reference site at Olna Firth was found to have the highest levels of 2-6-ring parent and branched PAHs, the highest concentration in one of the pooled sediments being 4,530 ng g(-1) dry weight. Values in the other two reference sites (Vaila Sound and Mangaster Voe) ranged from 248.7 to 902.2 ng g(-1) dry weight. PAH concentrations at the Zone sites (Sandsound Voe, Stromness Voe and Punds Voe) ranged from 641.0 to 2,766 ng g(-1) dry weight. The PAH data were normalised to the percentage of organic carbon and log-transformed prior to being analysed using principal component analysis. The mean total PAH concentrations for Zone sites were found not to be significantly different from the reference sites. The PAH concentration ratios were consistent with the main source of PAHs being pyrolysis. However, there was a petrogenic contribution, suggested by the presence of alkylated PAHs, with Punds Voe having the largest petrogenic hydrocarbon content. This was supported by the triterpane profiles and the presence of a UCM in the aliphatic chromatograms from Punds Voe sediments.

Platelet expression of tumour necrosis factor-alpha (TNF-alpha), TNF receptors and intercellular adhesion molecule-1 (ICAM-1) in patients with proliferative diabetic retinopathy

Microvascular complications of insulin-dependent diabetes mellitus (IDDM) have been strongly associated with platelet abnormalities, whilst TNF-alpha has been implicated in the pathogenesis of this condition. However, at present it is not clear whether human circulating platelets express TNF-alpha or TNF receptors (TNF-R) or whether impaired expression of these molecules and of the TNF-reactive adhesion molecule ICAM-1 may be associated with platelet abnormalities in patients with IDDM. On this basis we investigated the platelet expression of these molecules in patients with IDDM complicated or uncomplicated by proliferative diabetic retinopathy (PDR) and in healthy subjects. We observed that the proportion of platelets staining for TNF-alpha was significantly higher in IDDM patients with active PDR than in patients without microvascular complications (P = 0.0078), quiescent PDR (P = 0.003) or healthy subjects (P = 0.0013). Patients with active PDR also showed a higher proportion of platelets expressing TNF-RI (P = 0. 0052) and TNF-RII (P = 0.015) than healthy controls or patients with quiescent PDR (P = 0.009 and 0.0006, respectively). In addition, the percentage of ICAM-1+ platelets was significantly higher in patients with active PDR than in patients with quiescent PDR (P = 0.0065) or normal subjects (P = 0.013). There was a direct correlation between platelet expression of TNF-alpha and that of TNF-R in PDR patients, indicating that platelet staining for TNF-alpha may be due to binding of this cytokine to its receptors. The results suggest that increased platelet expression of TNF-alpha, TNF-R and ICAM-1 in IDDM patients may constitute important markers of thrombocyte abnormalities during the development of microvascular complications of diabetes mellitus.

Burnout and leadership in community mental health systems

This study investigated whether aspects of burnout in clinical staff in community mental health agencies were systematically related to aspects of leadership behavior and quality of supervision of clinical supervisors. Burnout was measured by the Maslach Burnout Inventory, leadership behavior was measured by the Leadership Practices Inventory, and clinical supervision by a scale constructed by the authors. Significant, though moderate relationships were found between the measures, and the implications for an organizational model of burnout, as well as prevention of burnout in mental health professionals are discussed.

Predominance of MMP-1 and MMP-2 in epiretinal and subretinal membranes of proliferative vitreoretinopathy

Matrix metalloproteinases (MMPs) and their natural inhibitors (TIMPs) play an important role in matrix remodelling and their involvement in the formation of scar-like tissue in proliferative vitreoretinopathy (PVR) is unknown. In this study we investigated epiretinal and subretinal membranes of PVR for the presence of selected MMPs and TIMPs whose substrates are extracellular matrix components of these membranes. We examined 23 epiretinal membranes and 15 subretinal membranes of PVR for deposition of interstitial collagenase (MMP-1), stromelysin-1 (MMP-3), gelatinase A (MMP-2), gelatinase B (MMP-9) and two tissue inhibitors of metalloproteinases (TIMP-1 and TIMP-2) by immunohistochemical methods. Normal cadaveric retinas served as controls. We observed that a large proportion of epiretinal and subretinal membranes stained for MMP-1 and MMP-2, whilst MMP-3, MMP-9, TIMP-1 and TIMP-2 were only observed in a small proportion of specimens. Normal cadaveric retinas stained for MMP-1 but not for MMP-2, MMP-3, MMP-9 or TIMP-1. TIMP-2 positive cells were observed within the inner and outer nuclear cell layers of normal retina. Presence of MMP-2, MMP-3 and TIMP-1 in epiretinal and subretinal membranes of PVR but not in normal retina indicates that these molecules may play an important role during the healing process that follows rhegmatogenous retinal detachment. An understanding of the mechanisms that control production and activity of these enzymes and their inhibitors may aid in the design of new therapeutic approaches to treat and prevent PVR.

KATP channel blocking actions of quaternary ions play no role in their antiproliferative action on mouse leukaemia and rat vascular smooth muscle cells in vitro

1. The aim of the present study was to investigate the possibility that, in the two cell lines examined, alterations in cell growth caused by lipophilic quaternary ions may involve KATP channels. We examined the effect of tetraphenylphosphonium (TPP), tetraphenylboron (TPB), rhodamine 123, dequalinium chloride (DECA) and the non-quaternary ion cisplatin on the proliferation of L1210 mouse leukaemia cells and rat smooth muscle cells in vitro. The KATP channel opener levcromakalim (LKM) and the KATP channel antagonist glibenclamide were also tested. 2. From growth-inhibition studies, the rank order of potency (based on pIC50 values) using L1210 leukaemia cells was: DECA (6.61) > cisplatin (6.09) = rhodamine 123 (6.01) > TPP (5.61) > TPB (4.25). Levcromakalim and glibenclamide were found to be inactive at the maximum concentrations used (100 mumol/L). A different rank order of potency was obtained in rat aortic smooth muscle cells: cisplatin (6.33) > DECA (5.67) > TPP (4.96) > rhodamine 123 (4.1). Tetraphenylboron (30 mumol/L), LKM (100 mumol/L) and glibenclamide (100 mumol/L) were found to be inactive. 3. When the negatively charged TPB (30 mumol/L) was combined with some of the active agents, the potency of the active agents was increased. Thus, in L1210 cells, rhodamine 123, DECA and TPP were all more potent at inhibiting cell growth in the presence of TPB. Tetraphenylboron had no effect on cisplatin in this cell line. In rat smooth muscle cells, TPB (30 mumol/L) potentiated the effect of rhodamine 123 but had no effect on the actions of cisplatin, DECA or TPP. 4. In functional studies, rhodamine 123 was a weak antagonist of the vasorelaxant responses to the KATP channel opener LKM in the porcine right circumflex artery in vitro. The pKB value obtained for rhodamine 123 at 100 mumol/L was 4.95. Dequalinium chloride was inactive. 5. We found no correlation between the actions of the compounds tested to antagonise KATP channels and their ability to inhibit cell proliferation. In addition, compounds known to regulate KATP channel activity failed to influence proliferative rates. These results suggest that KATP channels are not involved in the antiproliferative action of TPP and other quaternary ions in the two cell lines studied.