A record of microplastic in the marine nearshore waters of South Georgia.

The polar plastics research community have recommended the spatial coverage of microplastic investigations in Antarctica and the Southern Ocean be increased. Presented here is a baseline estimate of microplastics in the nearshore waters of South Georgia, the first in situ study of the north-east coast of the island. Our results show that the microplastic concentration in seawater at twelve stations in proximity to King Edward Point Research Station ranged from 1.75 ± 5.17 MP/L (mean ± SD), approximately one order of magnitude higher than similar studies of sea surface waters south of the Polar Front. Levels of microplastics in freshwater (sampled from Gull Lake) and precipitation (collected adjacent to the research station) were 2.67 ± 3.05 MP/L, and 4.67 ± 3.21 MP/L respectively. There was no significant difference in the microplastic concentration between seawater sites, and no significant bilateral relationship between concentration and distance from the research station outlets. We report an average concentration of 1.66 ± 3.00 MP/L in wastewater collected from the research station but overall, the counts of microplastics were too low to attach any statistical significance to the similarity in the microplastic assemblages of seawater and wastewater, or assemblages retrieved from penguin species in the region in other studies. Using a calculation described in contemporary literature we estimate the number of microfibres potentially being released from ships and stations annually in the region but acknowledge that further samples are needed to support the figures generated. More extensive research into microplastic distribution, characteristics, and transport in the region is recommended to fully compute the level of risk which this pollutant represents to the ecosystem health of this remote region.

The missing sink - quantification, categorisation and sourcing of beached macro-debris in the Scottish Orkney Islands.

Around the coastline of the UK, macro-debris has been observed in average densities of over 700 items per metre. Systematic beach-cleans were conducted at 35 sites around the Scottish Orkney Islands, in order to quantify and categorise the level of marine debris found there. Litter was collected from 100 m transects and categorised by its material, broad source (terrestrial or marine) and potential sector source. Variation between sites, and the relative contribution of pre-determined environmental variables in influencing said variation, were analysed using the "capscale" function for a canonical analysis of principle coordinates (CAP). 513 items/m were observed, (77% plastic), with "String/cord (<1cm diameter)" being the most abundant and widely distributed litter type. 47% of macro-debris was attributed to the fishing sector and < 10% to leisure, living and tourism-associated activities. Conversely, the unique regional hydrodynamics must be examined further, before the source of any given item can be categorically assigned.

Evidence from in vitro and in vivo studies showing that nuclear factor-κB within the pituitary folliculostellate cells and corticotrophs regulates adrenocorticotrophic hormone secretion in experimental endotoxaemia.

The hypothalamic-pituitary-adrenocortical (HPA) responses to bacterial infection are mediated, in part, by the actions of lipopolysaccharide (LPS) on pituitary folliculostellate (FS) cells that release pro-inflammatory cytokines [e.g. interleukin (IL)-6] and thereby facilitate adrenocorticotrophic hormone (ACTH) release from neighbouring corticotrophs. In the present study, two murine pituitary cell lines [TtT/GF (FS cells) and AtT20 D16:16 (corticotrophs)], alone and in co-culture, and an in vivo model of endotoxaemia were used to examine the potential role of nuclear factor-kappa B (NF-κB) in mediating LPS-induced ACTH secretion. Both cell lines expressed mRNAs for the key components of the LPS signalling system. LPS stimulated IL-6 release from TtT/GF cells via a glucocorticoid-sensitive, NF-κB-dependent mechanism; it also activated NF-κB in AtT20 cells, as did corticotrophin-releasing hormone (CRH). IL-6 potentiated (but LPS reduced) the stimulatory effects of CRH on ACTH release from AtT20 cells, whereas blockade of NF-κB (SC-514) increased the ACTH release induced by CRH in the presence or absence of LPS. In co-cultures, CRH and LPS acted synergistically to induce release of both IL-6 and ACTH. However, although SC-514 suppressed the release of IL-6 evoked by CRH and LPS, it potentiated the concomitant increase in ACTH release. In vivo both immunological (LPS) and psychological (restraint) stress increased intrapituitary NF-κB, whereas an NF-κB inhibitor (PHA781535E) attenuated the LPS-induced release of ACTH and abolished the HPA response to restraint stress. The results obtained in the present study support the premise that NF-κB plays an important role in mediating LPS signalling in the anterior pituitary gland, particularly in relation to IL-6 and ACTH secretion, and provide novel evidence that NF-κB blockade in vivo compromises stress-induced ACTH release.

Systematic review of rotator cuff tears in workers' compensation patients.

BACKGROUND: The burden imposed by workplace rotator cuff (RC) injuries has been reasonably defined. However, literature associated with the demographic characteristics and 'best practices' to manage such injuries among workers' compensation (WC) patients is scant. AIMS: To consolidate the existing literature on full-thickness RC tears among WC patients. Subject, shoulder and injury characteristics were examined to determine if and how WC recipients may differ from their non-compensable counterparts. METHODS: A systematic search (databases, clinical practice guideline web resources, conference proceedings and reference lists) revealed 450 abstracts. Two blinded reviewers independently assessed abstracts for inclusion. Sixty abstracts were subsequently included in a blinded full manuscript review. Seventeen of these manuscripts (3.8% of sample; 11 intervention and 6 determinant) were included in the present review. RESULTS: Previous studies demonstrate that operative interventions are appropriate for full-thickness RC tears as substantial gains in range of motion, strength and quality of life were witnessed within the first post-operative year. Non-operative interventions, including workplace-based work hardening, physical therapy and the use of an early referral system, were shown to improve outcomes. Conflicting results exist with respect to determinants such as age and sex. Importantly, WC patients had consistently poorer outcomes than non-WC patients. CONCLUSIONS: Our results show that although WC patients experience substantial benefits from various treatments for full-thickness RC tears, disparities exist between them and their non-WC counterparts. The lack of WC-specific literature limited our results. Larger studies, particularly ones comparing WC patients with their non-compensable counterparts, are crucial to allow for future evidence-based recommendations.

Clinical characteristics and outcomes of bilateral breast cancer in an Australian cohort.

PURPOSE: Uncertainty remains about the impact of bilateral breast cancer. Characteristics and outcomes of unilateral and bilateral breast cancer were compared within an Australian multi-institutional cohort. METHODS: Demographic, tumour and treatment characteristics were compared among unilateral (n = 2336) and bilateral cases (52 synchronous, 35 metachronous) using descriptive analyses. Disease-specific outcomes were investigated using Cox regression modelling to adjust for prognostic and treatment factors. RESULTS: Factors associated with increased risk of bilateral breast cancer included lobular histology (p = 0.046), family history (p = 0.025) and metropolitan residence (p = 0.006). Mastectomy was more common for bilateral cases (p = 0.001) while radiotherapy was less common (p = 0.015). Index metachronous cases were less likely to receive hormonal therapy (p = 0.001). Five-year survivals for metachronous, synchronous and unilateral cases were 79%, 88% and 94%, respectively. Poorer outcomes remained after adjusting for prognostic factors [HR = 2.26, 1.21-4.21]. CONCLUSION: Our results confirm international findings indicating worse outcomes from bilateral compared with unilateral breast cancer.

Formyl peptide receptors and the regulation of ACTH secretion: targets for annexin A1, lipoxins, and bacterial peptides.

The N-formyl peptide receptors (FPRs) are a family of G-protein coupled receptors that respond to proinflammatory N-formylated bacterial peptides (e.g., formyl-Met-Leu-Phe, fMLF) and, thus, contribute to the host response to bacterial infection. Paradoxically, a growing body of evidence suggests that some members of this receptor family may also be targets for certain anti-inflammatory molecules, including annexin A1 (ANXA1), which is an important mediator of glucocorticoid (GC) action. To explore further the potential role of FPRs in mediating ANXA1 actions, we have focused on the pituitary gland, where ANXA1 has a well-defined role as a cell-cell mediator of the inhibitory effects of GCs on the secretion of corticotrophin (ACTH), and used molecular, genetic, and pharmacological approaches to address the question in well-established rodent models. Reverse transcriptase-polymerase chain reaction (RT-PCR) analysis identified mRNAs for four FPR family members in the mouse anterior pituitary gland, Fpr-rs1, Fpr-rs2, Fpr-rs6, and Fpr-rs7. Functional studies confirmed that, like dexamethasone, ANXA1 and two ANXA1-derived peptides (ANXA1(1-188) and ANXA1(Ac2-26)) inhibit the evoked release of ACTH from rodent anterior pituitary tissue in vitro. Fpr1 gene deletion failed to modify the pituitary responses to dexamethasone or ANXA1(Ac2-26). However, lipoxin A4 (LXA4, 0.02-2 microM, a lipid mediator with high affinity for Fpr-rs1) mimicked the inhibitory effects of ANXA1 on ACTH release as also did fMLF in high (1-100 microM) but not lower (10-100 nM) concentrations. Additionally, a nonselective FPR antagonist (Boc1, 100 microM) overcame the effects of dexamethasone, ANXA1(1-188), ANXA1(Ac2-26), fMLF, and LXA4 on ACTH release, although at a lower concentration (50 microM), it was without effect. Together, the results suggest that the actions of ANXA1 in the pituitary gland are independent of Fpr1 but may involve other FPR family members, in particular, Fpr-rs1 or a closely related receptor. They thus provide the first evidence for a role of the FPR family in the regulation of neuroendocrine function.

Time-specific effects of perinatal glucocorticoid treatment on anterior pituitary morphology, annexin 1 expression and adrenocorticotrophic hormone secretion in the adult female rat.

Perinatal glucocorticoid (GC) treatment is increasingly associated with long-term disturbances in hypothalamo-pituitary-adrenocortical function. In the male rat, such treatment induces profound molecular, morphological and functional changes in the anterior pituitary gland at adulthood. To determine whether these effects are sex-specific, we have examined the effects of perinatal dexamethasone treatment on the female pituitary gland, focusing on (i) the integrity of the annexin 1 (ANXA1) dependent regulatory effects of GCs on adrenocorticotrophic hormone (ACTH) release and (ii) corticotroph and folliculo-stellate (FS) cell morphology. Dexamethasone was given to pregnant (gestational days 16-19) or lactating (days 1-7 post partum) rats via the drinking water (1 microg/ml); controls received normal drinking water. Pituitary tissue from the female offspring was examined ex vivo at adulthood (60-90 days). Both treatment regimes reduced the intracellular and cell surface ANXA1 expression, as determined by western blot analysis and quantitative immunogold electron microscopic histochemistry. In addition, they compromised the ability of dexamethasone to suppress the evoked release of ACTH from the excised tissue in vitro, a process which requires the translocation of ANXA1 from the cytoplasm to the cell surface of FS cells. Although neither treatment regime affected the number of FS cells or corticotrophs, both altered the subcellular morphology of these cells. Thus, prenatal dexamethasone treatment increased while neonatal treatment decreased FS cell size and cytoplasmic area. By contrast, corticotroph size was unaffected by either treatment, as also was the size of the secretory granules. Corticotroph granule density and margination were, however, increased markedly by the prenatal treatment, while the neonatal treatment had no effect on granule density but decreased granule margination. Thus, perinatal dexamethasone treatment exerts long-term effects on the female pituitary gland, altering gene expression, cell morphology and the ANXA1-dependent GC regulation of ACTH secretion. The changes are similar but not identical to those reported in the male.

Lack of annexin 1 results in an increase in corticotroph number in male but not female mice.

Annexin 1 (ANXA1) is a member of the annexin family of phospholipid- and calcium-binding proteins with a well demonstrated role in early delayed (30 min to 3 h) inhibitory feedback of glucocorticoids in the pituitary. We have examined corticotrophs in wild-type and ANXA1 knockout mice to determine the effects of lack of ANXA1 in male and female animals. Anterior pituitary tissue from ANXA1 wild-type, heterozygote and null mice was fixed and examined (i) by confocal immunocytochemistry to determine the number of corticotrophs and (ii) by electron microscopy to examine the size, secretory granule population and secretory machinery of corticotrophs. No differences in these parameters were detected in female mice. In male ANXA1 null mice, there were approximately four-fold more corticotrophs than in wild-type animals. However, the corticotrophs in ANXA1 null mice were smaller and had reduced numbers of secretory granules (the reduction in granules paralleled the reduction in cell size). No differences in the numerical density of folliculo-stellate, gonadotroph, lactotroph or somatotroph cells were detected in male ANXA1 null mice. Plasma corticosterone, adrenocorticotrophic hormone (ACTH) and pituitary pro-opiomelanocortin mRNA were unchanged but pituitary ACTH content was increased in male ANXA1 null mice. Interleukin (IL)-6 pituitary content was significantly elevated in male and reduced in female ANXA1 null mice compared to wild-type. In conclusion, these data indicate that ANXA1 deficiency is associated with gender-specific changes in corticotroph number and structure, via direct actions of ANXA1 and/or indirect changes in factors such as IL-6.

The long-term effects of perinatal glucocorticoid exposure on the host defence system of the respiratory tract.

Glucocorticoids are used to mature the fetal lung at times of threatened premature delivery. These drugs modify leukocyte profiles when administered in adulthood, but their effects on the mature host defence system following administration during the perinatal period are incompletely understood. In this study, the long-term effects of perinatal dexamethasone exposure on rodent host defence cells in the pulmonary airspaces, the perivascular compartment of the lung, and the blood were investigated. Rats were treated prenatally (gestational days 16-19) or neonatally (postnatal days 1-7) by inclusion of dexamethasone in the mothers' drinking water (1 microg/ml). The pups were then allowed to develop to adulthood (P60-80), at which time respiratory tissues were collected for light and electron microscopy and bronchoalveolar lavage (BAL), and blood for cell count and fluorescent activated cell-sorting (FACS) analysis. Prenatal treatment had no effect on any parameter examined. Following neonatal dexamethasone exposure, light microscopy of the lung tissue revealed a significant reduction in the number of cells in the perivascular space in both the central and the peripheral regions of the adult lung, but no differences in the number of cells in the airspaces. Neonatal dexamethasone exposure was also characterized by a significant reduction in the total number of white cells in the peripheral blood in adulthood and in particular, the number of lymphocytes relative to neutrophils was significantly reduced at maturity in these animals. The results show that neonatal, but not prenatal, dexamethasone exposure significantly alters the distribution of host defence cells in the blood and lung at maturity compared with control animals. The early neonatal period is characterized by the stress hyporesponsive period in the rat, when endogenous glucocorticoid levels are very low. Therefore, exogenous glucocorticoids administered during this time are likely to have marked "programming" effects on glucocorticoid-sensitive tissues.

Post-translational modification plays an essential role in the translocation of annexin A1 from the cytoplasm to the cell surface.

Annexin A1 (ANXA1) has an important role in cell-cell communication in the host defense and neuroendocrine systems. In both systems, its actions are exerted extracellularly via membrane-bound receptors on adjacent sites after translocation of the protein from the cytoplasm to the cell surface of adjacent cells. This study used molecular, microscopic, and pharmacological approaches to explore the mechanisms underlying the cellular exportation of ANXA1 in TtT/GF (pituitary folliculo-stellate) cells. LPS caused serine-phosphorylation of ANXA1 (ANXA1-S27-PO4) and translocation of the phosphorylated protein to the cell membrane. The fundamental requirement of phosphorylation for membrane translocation was confirmed by immunofluorescence microscopy on cells transfected with wild-type or mutated (S27/A) ANXA1 constructs tagged with enhanced green fluorescence protein. The trafficking of ANXA1-S27-PO4 to the cell surface was dependent on PI3-kinase and MAP-kinase. It also required HMG-coenzyme A and myristoylation. The effects of HMG-coenzyme A blockade were overcome by mevalonic acid (the product of HMG-coenzyme A) and farnesyl-pyrophosphate but not by geranyl-geranylpyrophosphate or cholesterol. Together, these results suggest that serine-27 phosphorylation is essential for the translocation of ANXA1 across the cell membrane and also identify a role for isoprenyl lipids. Such lipids could target consensus sequences in ANXA1. Alternatively, they may target other proteins in the signal transduction cascade (e.g., transporters).

Perinatal glucocorticoid treatment disrupts the hypothalamo-lactotroph axis in adult female, but not male, rats.

This study aimed to test the hypothesis that the tuberoinfundibular dopaminergic neurons of the arcuate nucleus and/or the lactotroph cells of the anterior pituitary gland are key targets for the programming effects of perinatal glucocorticoids (GCs). Dexamethasone was administered noninvasively to fetal or neonatal rats via the mothers' drinking water (1 mug/ml) on embryonic d 16-19 or neonatal d 1-7, and control animals received normal drinking water. At 68 d of age, the numbers of tyrosine hydroxylase-positive (TH+) cells in the arcuate nucleus and morphometric parameters of pituitary lactotrophs were analyzed. In control animals, striking sex differences in TH+ cell numbers, lactotroph cell size, and pituitary prolactin content were observed. Both pre- and neonatal GC treatment regimens were without effect in adult male rats, but in females, the overriding effect was to abolish the sex differences by reducing arcuate TH+ cell numbers (pre- and neonatal treatments) and reducing lactotroph cell size and pituitary prolactin content (prenatal treatment only) without changing lactotroph cell numbers. Changes in circulating prolactin levels represented a net effect of hypothalamic and pituitary alterations that exhibited independent critical windows of susceptibility to perinatal GC treatments. The dopaminergic neurons of the hypothalamic periventricular nucleus and the pituitary somatotroph populations were not significantly affected by either treatment regimen in either sex. These data show that the adult female hypothalamo-lactotroph axis is profoundly affected by perinatal exposure to GCs, which disrupts the tonic inhibitory tuberoinfundibular dopaminergic pathway and changes lactotroph morphology and prolactin levels in the pituitary and circulation. These findings provide new evidence for a long-term disruption in prolactin-dependent homeostasis in females, but not males, after inappropriate GC exposure in perinatal life.

Perinatal glucocorticoid treatment produces molecular, functional, and morphological changes in the anterior pituitary gland of the adult male rat.

Stress or glucocorticoid (GC) treatment in perinatal life can induce long-term changes in the sensitivity of the hypothalamo-pituitary-adrenocortical axis to the feedback actions of GCs and, hence, in GC secretion. These changes have been ascribed largely to changes in the sensitivity of the limbic system, and possibly the hypothalamus, to GCs. Surprisingly, the possibility that early life stress/GC treatment may also exert irreversible effects at the pituitary level has scarcely been addressed. Accordingly, we have examined the effects of pre- and neonatal dexamethasone treatment on the adult male pituitary gland, focusing on the following: 1) the integrity of the acute annexin 1 (ANXA1)-dependent inhibitory actions of GCs on ACTH secretion, a process requiring ANXA1 release from folliculostellate (FS) cells; and 2) the morphology of FS cells and corticotrophs. Dexamethasone was given to pregnant (d 16-19) or lactating (d 1-7 postpartum) rats via the drinking water (1 microg/ml); controls received normal drinking water. Pituitary tissue from the offspring was examined ex vivo at d 90. Both treatment regimens reduced ANXA1 expression, as assessed by Western blotting and quantitative immunogold labeling. In particular, the amount of ANXA1 located on the outer surface of the FS cells was reduced. By contrast, IL-6 expression was increased, particularly by the prenatal treatment. Pituitary tissue from untreated control rats responded to dexamethasone with an increase in cell surface ANXA1 and a reduction in forskolin-induced ACTH release. In contrast, pituitary tissue from rats treated prenatally or neonatally with dexamethasone was unresponsive to the steroid, although, like control tissue, it responded readily to ANXA1, which readily inhibited forskolin-driven ACTH release. Prenatal dexamethasone treatment reduced the size but not the number of FS cells. It also caused a marked reduction in corticotroph number and impaired granule margination without affecting other aspects of corticotroph morphology. Similar but less marked effects on pituitary cell morphology and number were evident in tissue from neonatally treated rats. Our study shows that, when administered by a noninvasive process, perinatal GC treatment exerts profound effects on the adult pituitary gland, impairing the ANXA1-dependent GC regulation of ACTH release and altering the cell profile and morphology.

Altered mesencephalic dopaminergic populations in adulthood as a consequence of brief perinatal glucocorticoid exposure.

Early exposure to stressors is strongly associated with enduring effects on central nervous system function, but the mechanisms and neural substrates involved in this biological 'programming' are unclear. This study tested the hypothesis that inappropriate exposure to glucocorticoid stress hormones (GCs) during critical periods of development permanently alters the mesencephalic dopaminergic populations in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). Using a rat model, the synthetic GC dexamethasone was added to the maternal drinking water during gestational days 16-19 or over the first week of postnatal life. In adulthood, the effects upon tyrosine hydroxylase immunopositive (TH+) cell numbers in the midbrain, and monoamine levels in the forebrain, of the adult offspring were assessed and compared with control offspring whose dams received normal drinking water. In the VTA, both prenatal and postnatal dexamethasone treatment increased TH+ cell numbers by approximately 50% in males and females. Although prenatal dexamethasone treatment also increased TH+ cell numbers in the SNc by 40-50% in males and females, postnatal treatment affected females only by increasing TH+ cell numbers by approximately 30%. In comparison, similar changes were not detected in the monoamine levels of the dorsolateral striatum, nucleus accumbens or infralimbic cortex of either males or females, which is a feature likely to reflect adaptive changes in these pathways. These studies demonstrate that the survival or phenotypic expression of VTA and SNc dopaminergic neurones is profoundly influenced by brief perinatal exposure to GCs at times when endogenous levels are normally low. These findings are the first to demonstrate permanent changes in the cytoarchitecture within midbrain dopamine nuclei after perinatal exposure to stress hormones and implicate altered functionality. Thus, they have significance for the increasing use of GCs in perinatal medicine and indicate potential mechanisms whereby perinatal distress may predispose to the development of a range of psychiatric conditions in later life.

Evidence from studies on co-cultures of TtT/GF and AtT20 cells that Annexin 1 acts as a paracrine or juxtacrine mediator of the early inhibitory effects of glucocorticoids on ACTH release.

Annexin 1 (ANXA1) is a key mediator of the inhibitory effects of glucocorticoids on adrenocorticotropic hormone (ACTH) release, which develop within 1-2 h of a steroid challenge. Our previous studies, which showed that (i) ANXA1 is expressed principally by the nonsecretory folliculo-stellate cells in the pituitary gland; (ii) glucocorticoids cause the exportation of ANXA1 from these cells; and (iii) corticotrophs express specific ANXA1 binding sites, led us to propose that ANXA1 serves as a paracrine or juxtacrine mediator of glucocorticoids. To address this hypothesis, we examined ANXA1-dependent glucocorticoid actions in co-cultures of murine corticotroph (AtT20 clone D1) and folliculo-stellate (TtT/GF) cell lines. ANXA1 mRNA and protein were found in abundance in TtT/GF cells but neither was detectable in the AtT20 cells. AtT20 cells (alone and in co-culture with TtT/GF cells) responded to corticotropin-releasing hormone (CRH) (0.1-1 micro m) with increased ACTH release. The CRH-stimulated release of ACTH from AtT20 cells cultured alone was unaffected by preincubation with dexamethasone (Dex, 100 nm); by contrast, in co-cultures of AtT20 and TtT/GF cells, the steroid readily inhibited the secretory response to CRH. The effects of Dex on ACTH release were mimicked by N-terminal ANXA1 fragments (ANXA1Ac2-26, 2 micro g/ml and ANXA11-188, 0.1 ng/ml) and reversed by mifepristone (1 micro m) and by an antisense oligodeoxynucleotide (ODN) to ANXA1 (50 nm) but not by control ODNs. The antisense ODN also specifically blocked the Dex-induced externalization of ANXA1 from TtT/GF cells. Immunofluorescence imaging of the co-cultures localized the exported protein to the vicinity of the AtT20 cells and identified ANXA1 binding sites on these cells. These results provide functional and histological evidence to support our premise that the early inhibitory effects of glucocorticoids on ACTH release are dependent upon paracrine/juxtacrine actions of ANXA1 derived from folliculo-stellate cells.

Kinase-dependent regulation of the secretion of thyrotrophin and luteinizing hormone by glucocorticoids and annexin 1 peptides.

Our previous studies have identified a role for annexin 1 (ANXA1), a protein produced by the pituitary folliculostellate cells, as a paracrine/juxtacrine mediator of the acute regulatory effects of glucocorticoids on the release of adrenocorticotropic hormone and other pituitary hormones. In the present study, we focused on the secretion of thyroid stimulating hormone (TSH) and luteinizing hormone (LH) and used a battery of ANXA1-derived peptides to identify the key domains in the ANXA1 molecule that are critical to the inhibition of peptide release. In addition, as ANXA1 is a substrate for protein kinase C (PKC) and tyrosine kinase, we examined the roles of these kinases in the manifestation of the ANXA1-dependent inhibitory actions of dexamethasone on TSH and LH release. Dexamethasone suppressed the forskolin-induced release of TSH and LH from rat anterior pituitary tissue in vitro. Its effects were mimicked by human recombinant ANXA1 (hrANXA1) and a truncated protein, ANXA1(1-188). ANXA1(Ac2-26), also suppressed stimulated peptide release but it lacked both the potency and the efficacy of the parent protein. Shorter N-terminal ANXA1 sequences were without effect. The PKC inhibitor PKC(19-36) abolished the inhibitory actions of dexamethasone on the forskolin-evoked release of TSH and LH; it also attenuated the inhibitory actions of ANXA1(Ac2-26). Similar effects were produced by annexin 5 (ANXA5) which sequesters PKC in other systems. By contrast, the tyrosine kinase inhibitors, p60v-src (137-157) and genistein, had no effect on the secretion of TSH or LH alone or in the presence of forskolin and/or dexamethasone. Dexamethasone caused the translocation of a tyrosine-phosphorylated species of ANXA1 to the surface of pituitary cells. The total amount of ANXA1 exported from the cells in response to the steroid was unaffected by tyrosine kinase blockade. However, the degree of tyrosine-phosphorylation of the exported protein was markedly reduced by genistein. These results suggest that (i) the ANXA1-dependent inhibitory actions of dexamethasone on the release of TSH and LH require PKC and sequences in the N-terminal domain of ANXA1, but are independent of tyrosine kinase, and (ii) while dexamethasone induces the cellular exportation of a tyrosine-phosphorylated species of ANXA1, tyrosine phosphorylation per se is not critical to the steroid-induced passage of ANXA1 across the membrane.

Steroid effects on secretion from subsets of lactotrophs: role of folliculo-stellate cells and annexin 1.

Prolactin secretion is controlled by the hypothalamus, and by circulating steroids; oestrogens stimulate, but glucocorticoids inhibit prolactin release. Lactotrophs express intracellular receptors for oestrogens, but apparently not glucocorticoids. Therefore, a genomic effect of oestrogens could be direct, but that of glucocorticoids appears to be indirect. Lactotrophs are not a homogeneous cell population: some have large irregular dense-cored vesicles, others have small round vesicles, but the functional significance of this inhomogeneity is far from clear. Oestradiol and testosterone can stimulate rapid release of prolactin selectively from type II lactotrophs characterised by small round vesicles. Progesterone and other steroids do not exert this effect, which results from a non-genomic action of oestradiol and testosterone. Glucocorticoid inhibition of secretagogue-induced prolactin secretion is mimicked by annexin 1 (lipocortin 1), a protein induced by glucocorticoids in the pituitary and many other tissues, and can be blocked by annexin 1 immunoneutralisation and antisense. Glucocorticoid inhibition of ACTH and growth hormone secretion also involves annexin 1. Pituitary annexin 1 is located in folliculo-stellate cells; these express glucocorticoid receptors, and glucocorticoids induce annexin-1 synthesis. Annexin 1 is externalised from folliculo-stellate cells in response to glucocorticoids, despite the fact that it lacks a secretory signal sequence and is not packaged in vesicles. Inhibition of annexin 1 externalisation by glyburide suggests involvement of an ABC (ATP-binding cassette) transporter in externalisation. Both oestradiol and glucocorticoids therefore influence the secretion of prolactin by novel direct and indirect mechanisms, in addition to their much better understood effects on transcription via classical intracellular steroid receptors.

The annexin-1 knockout mouse: what it tells us about the inflammatory response.

The 37kDa protein annexin 1 (Anx-1; lipocortin 1) is a glucocorticoid-regulated protein that has been implicated in the regulation of phagocytosis, cell signalling and proliferation, and postulated to be a mediator of glucocorticoids action in inflammation and in the control of anterior pituitary hormone release. Immuno-neutralisation or antisense strategies support this hypothesis as they can reverse the effect of glucocorticoids in several systems. We recently generated a line of mice lacking the Anx-1 gene noting that some tissues taken from such animals exhibited an increased expression of several proteins including COX-2 and cPLA2. In models of experimental inflammation, Anx-1(-/-) mice exhibit an exaggerated response and a partial or complete resistance to the anti-inflammatory effects of glucocorticoids. Several other anomalies were noted including abnormal leukocyte adhesion molecule expression, an increased spontaneous migratory behaviour of PMN in Anx-1(-/-) mice and a resistance in Anx-1(-/-) macrophages to glucocorticoid inhibition of superoxide generation. This paper reviews these and other data in the light of the development of the 'second messenger' hypothesis of glucocorticoid action.

Opposing influences of glucocorticoids and interleukin-1beta on the secretion of growth hormone and ACTH in the rat in vivo: role of hypothalamic annexin 1.

1. This study exploited established immunoneutralization protocols and an N-terminal annexin 1 peptide (annexin 1(Ac2 - 26)) to advance our knowledge of the role of annexin 1 as a mediator of acute glucocorticoid action in the rat neuroendocrine system in vivo. 2. Rats were treated with corticosterone (500 microg kg(-1), i.p.) or annexin 1(Ac2 - 26) (0.1 - 10 ng rat(-1), i.c.v.) and 75 min later with interleukin 1beta (IL-1beta, 10 ng rat(-1), i.c.v. or 500 microg kg(-1), i.p). Blood was collected 1 h later for hormone immunoassay. Where appropriate, anti-annexin 1 polyclonal antiserum (pAb) was administered subcutaneously or centrally prior to the steroid challenge. 3. Corticosterone did not affect the resting plasma corticotrophin (ACTH) concentration but suppressed the hypersecretion of ACTH induced by IL-1beta (i.p. or i.c.v.). Its actions were quenched by anti-annexin 1 pAb (s.c. or i.c.v) and mimicked by annexin 1(Ac2 - 26). 4. By contrast, corticosterone provoked an increase in serum growth hormone (GH) which was ablated by central but not peripheral administration of anti-annexin 1 pAb. IL-1beta (i.c.v. or i.p.) did not affect basal GH but, when given centrally but not peripherally, it abolished the corticosterone-induced hypersecretion of GH. Annexin 1(Ac2 - 26) (i.c.v.) also produced an increase in serum GH which was prevented by central injection of IL-1beta. 5. The results support the hypothesis that the acute regulatory actions of glucocorticoids on hypothalamo-pituitary-adrenocortical function require annexin 1. They also provide novel evidence that the positive influence of the steroids on GH secretion evident within this timeframe is effected centrally via an annexin 1-dependent mechanism which is antagonized by IL-1beta.

Nodular fasciitis of the breast simulating breast cancer on imaging.

Nodular fasciitis is a rare benign soft tissue tumour of the breast that clinically and radiologically can mimic invasive duct carcinoma. The clinical, radiological and pathological findings of nodular fasciitis of the breast in a 38-year-old woman, who presented with a palpable lesion in the upper inner aspect of the left breast, are described. The tumour is characterized histologically by a stellate spindle cell tumour with a focal myxoid background containing scattered inflammatory cells and microhaemorrhages. Pathological assessment of the lesion is essential in making the diagnosis.