Characterisation and correction of polarisation effects in fluorescently labelled fibres

Many biological structures take the form of fibres and filaments, and quantitative analysis of fibre organisation is important for understanding their functions in both normal physiological conditions and disease. In order to visualise these structures, fibres can be fluorescently labelled and imaged, with specialised image analysis methods available for quantifying the degree and strength of fibre alignment. Here we show that fluorescently labelled fibres can display polarised emission, with the strength of this effect varying depending on structure and fluorophore identity. This can bias automated analysis of fibre alignment and mask the true underlying structural organisation. We present a method for quantifying and correcting these polarisation effects without requiring polarisation-resolved microscopy and demonstrate its efficacy when applied to images of fluorescently labelled collagen gels, allowing for more reliable characterisation of fibre microarchitecture.

Autocrine IL-6 drives cell and extracellular matrix anisotropy in scar fibroblasts

Fibrosis is associated with dramatic changes in extracellular matrix (ECM) architecture of unknown etiology. Here we exploit keloid scars as a paradigm to understand fibrotic ECM organization. We reveal that keloid patient fibroblasts uniquely produce a globally aligned ECM network in 2-D culture as observed in scar tissue. ECM anisotropy develops after rapid initiation of a fibroblast supracellular actin network, suggesting that cell alignment initiates ECM patterning. Keloid fibroblasts produce elevated levels of IL-6, and autocrine IL-6 production is both necessary and sufficient to induce cell and ECM alignment, as evidenced by ligand stimulation of normal dermal fibroblasts and treatment of keloid fibroblasts with the function blocking IL-6 receptor monoclonal antibody, tocilizumab. Downstream of IL-6, supracellular organization of keloid fibroblasts is controlled by activation of cell-cell adhesion. Adhesion formation inhibits contact-induced cellular overlap leading to nematic organization of cells and an alignment of focal adhesions. Keloid fibroblasts placed on isotropic ECM align the pre-existing matrix, suggesting that focal adhesion alignment leads to active anisotropic remodeling. These results show that IL-6-induced fibroblast cooperativity can control the development of a nematic ECM, highlighting both IL-6 signaling and cell-cell adhesions as potential therapeutic targets to inhibit this common feature of fibrosis.

Loss of RhoE Function in Dermatofibroma Promotes Disorganized Dermal Fibroblast Extracellular Matrix and Increased Integrin Activation

Dermatofibromas (DFs) are common, benign fibrous skin tumors that can occur at any skin site. In most cases, DFs are solitary and sporadic, but a few are multiple and familial, and the mechanisms leading to these lesions are currently unclear. Using exome sequencing, we have identified a heterozygous variant in a pedigree with autosomal dominant multiple familial DF within RND3 (c.692C>T,p.T231M) that encodes for the small GTPase RhoE, a regulator of the actin cytoskeleton. Expression of T231M-RhoE or RhoE depletion using CRISPR in human dermal fibroblasts increased proliferation and adhesion to extracellular matrix through enhanced β1 integrin activation and more disorganized matrix. The enzyme PLOD2 was identified as a binding partner for RhoE, and the formation of this complex was disrupted by T231M-RhoE. PLOD2 promotes collagen cross-linking and activation of β1 integrins, and depleting PLOD2 in T231M-RhoE-expressing cells reduced T231M-RhoE-mediated β1 integrin activation and led to increased matrix alignment. Immunohistochemical analysis revealed reduced expression of RhoE but increased expression of PLOD2 in the dermis of DF skin samples compared with that of the controls. Our data show that loss of RhoE function leads to increased PLOD2 activation, enhancing integrin activation and leading to a disorganized extracellular matrix, contributing to DF.

Comorbidities of Keloid and Hypertrophic Scars Among Participants in UK Biobank

Importance

Keloids and hypertrophic scars (excessive scarring) are relatively understudied disfiguring chronic skin conditions with high treatment resistance.

Objective

To evaluate established comorbidities of excessive scarring in European individuals, with comparisons across ethnic groups, and to identify novel comorbidities via a phenome-wide association study (PheWAS).

Design, Setting, and Participants

This multicenter cross-sectional population-based cohort study used UK Biobank (UKB) data and fitted logistic regression models for testing associations between excessive scarring and a variety of outcomes, including previously studied comorbidities and 1518 systematically defined disease categories. Additional modeling was performed within subgroups of participants defined by self-reported ethnicity (as defined in UK Biobank). Of 502 701 UKB participants, analyses were restricted to 230078 individuals with linked primary care records.

Exposures

Keloid or hypertrophic scar diagnoses.

Main Outcomes and Measures

Previously studied disease associations (hypertension, uterine leiomyoma, vitamin D deficiency, atopic eczema) and phenotypes defined in the PheWAS Catalog.

Results

Of the 972 people with excessive scarring, there was a higher proportion of female participants compared with the 229 106 controls (65% vs 55%) and a lower proportion of White ethnicity (86% vs 95%); mean (SD) age of the total cohort was 64 (8) years. Associations were identified with hypertension and atopic eczema in models accounting for age, sex, and ethnicity, and the association with atopic eczema (odds ratio [OR], 1.68; 95% CI, 1.36-2.07; P < .001) remained statistically significant after accounting for additional potential confounders. Fully adjusted analyses within ethnic groups revealed associations with hypertension in Black participants (OR, 2.05; 95% CI, 1.13-3.72; P = .02) and with vitamin D deficiency in Asian participants (OR, 2.24; 95% CI, 1.26-3.97; P = .006). The association with uterine leiomyoma was borderline significant in Black women (OR, 1.93; 95% CI, 1.00-3.71; P = .05), whereas the association with atopic eczema was significant in White participants (OR, 1.68; 95% CI, 1.34-2.12; P < .001) and showed a similar trend in Asian (OR, 2.17; 95% CI, 1.01-4.67; P = .048) and Black participants (OR, 1.89; 95% CI, 0.83-4.28; P = .13). The PheWAS identified 110 significant associations across disease systems; of the nondermatological, musculoskeletal disease and pain symptoms were prominent.

Conclusions and Relevance

This cross-sectional study validated comorbidities of excessive scarring in UKB with comprehensive coverage of health outcomes. It also documented additional phenome-wide associations that will serve as a reference for future studies to investigate common underlying pathophysiologic mechanisms.

Seasonal Flight Patterns of Chrysodeixis includens (Lepidoptera: Noctuidae) in the Florida Panhandle and Inventory of Plusiine Species Cross-Attracted to Synthetic Pheromone

Chysodeixis includens (Walker) is a polyphagous economic pest in agricultural landscapes. To detect the occurrence of this pest in the field, trapping using sex pheromone lures is often implemented. However, other plusiine species are cross-attracted to these lures and may be misidentified as C. includens due to their morphological similarities. The objectives of this study were to provide region-specific information on the abundance of C. includens throughout the year as well as document the occurrence of related plusiines cross-attracted to C. includens sex pheromone traps in the Florida Panhandle. Twelve commercial fields of peanut and twelve commercial fields of cotton located across Escambia, Santa Rosa, and Jackson counties were monitored with Trécé delta traps baited with C. includens sex pheromone lures (Alpha Scents, Inc.; West Linn, OR) from June 2017 to June 2019. There was no difference in C. includens flight across dryland or irrigated fields. Identifications revealed that in addition to C. includens, the following species of the subfamily Plusiinae were crossed-attracted: Argyrogramma verruca (Fabricius) (Lepidoptera: Noctuidae), Trichoplusia ni (Hübner) (Lepidoptera: Noctuidae), Ctenoplusia oxygramma (Geyer) (Lepidoptera: Noctuidae), and Rachiplusia ou (Guenée) (Lepidoptera: Noctuidae). The occurrence of each species in the region and their flight phenology are documented. Chysodeixis includens abundance was greatest in September and decreased through December. Due to the high abundance of C. oxygramma and similar flight phenology to C. includens, this is the likeliest species to skew estimations and influence management decisions of C. includens, especially early in the crop season, when C. includens abundance is low.

A workflow for rapid unbiased quantification of fibrillar feature alignment in biological images

Measuring the organisation of the cellular cytoskeleton and the surrounding extracellular matrix (ECM) is currently of wide interest as changes in both local and global alignment can highlight alterations in cellular functions and material properties of the extracellular environment. Different approaches have been developed to quantify these structures, typically based on fibre segmentation or on matrix representation and transformation of the image, each with its own advantages and disadvantages. Here we present AFT-Alignment by Fourier Transform, a workflow to quantify the alignment of fibrillar features in microscopy images exploiting 2D Fast Fourier Transforms (FFT). Using pre-existing datasets of cell and ECM images, we demonstrate our approach and compare and contrast this workflow with two other well-known ImageJ algorithms to quantify image feature alignment. These comparisons reveal that AFT has a number of advantages due to its grid-based FFT approach. 1) Flexibility in defining the window and neighbourhood sizes allows for performing a parameter search to determine an optimal length scale to carry out alignment metrics. This approach can thus easily accommodate different image resolutions and biological systems. 2) The length scale of decay in alignment can be extracted by comparing neighbourhood sizes, revealing the overall distance that features remain anisotropic. 3) The approach is ambivalent to the signal source, thus making it applicable for a wide range of imaging modalities and is dependent on fewer input parameters than segmentation methods. 4) Finally, compared to segmentation methods, this algorithm is computationally inexpensive, as high-resolution images can be evaluated in less than a second on a standard desktop computer. This makes it feasible to screen numerous experimental perturbations or examine large images over long length scales. Implementation is made available in both MATLAB and Python for wider accessibility, with example datasets for single images and batch processing. Additionally, we include an approach to automatically search parameters for optimum window and neighbourhood sizes, as well as to measure the decay in alignment over progressively increasing length scales.

Metabolic perturbations in fibrosis disease

Metabolic changes occur in all forms of disease but their impact on fibrosis is a relatively recent area of interest. This review provides an overview of the major metabolic pathways, glycolysis, amino acid metabolism and lipid metabolism, and highlights how they influence fibrosis at a cellular and tissue level, drawing on key discoveries in dermal, renal, pulmonary and hepatic fibrosis. The emerging influence of adipose tissue-derived cytokines is discussed and brings a link between fibrosis and systemic metabolism. To close, the concept of targeting metabolism for fibrotic therapy is reviewed, drawing on lessons from the more established field of cancer metabolism, with an emphasis on important considerations for clinical translation.

Keloid tissue analysis discredits a role for myofibroblasts in disease pathogenesis

Myofibroblasts, renowned for their contractility and extracellular matrix production, are widely considered the key effector cells for nearly all scars resulting from tissue repair processes, ranging from normal scars to extreme fibrosis. For example, it is often assumed that myofibroblasts underpin the characteristics of keloid scars, which are debilitating pathological skin scars lacking effective treatments because of a poor understanding of the disease mechanisms. Here, we present primary and published transcriptional and histological evidence that myofibroblasts are not consistently present in primary keloid lesions, and when alpha-smooth muscle actin (αSMA)-positive cells are detected, they are not greater in number or expressing more αSMA than in normal or hypertrophic scars. In conclusion, keloid scars do not appear to require αSMA-positive myofibroblasts; continuing to consider keloids on a quantitative spectrum with normal or hypertrophic scars, with αSMA serving as a biomarker of disease severity, is hindering advancement of understanding and therapy development.

A developmental basis for the anatomical diversity of dermis in homeostasis and wound repair

The dermis has disparate embryonic origins; abdominal dermis develops from lateral plate mesoderm, dorsal dermis from paraxial mesoderm and facial dermis from neural crest. However, the cell and molecular differences and their functional implications have not been described. We hypothesise that the embryonic origin of the dermis underpins regional characteristics of skin, including its response to wounding. We have compared abdomen, back and cheek, three anatomical sites representing the distinct embryonic tissues from which the dermis can arise, during homeostasis and wound repair using RNA sequencing, histology and fibroblast cultures. Our transcriptional analyses demonstrate differences between body sites that reflect their diverse origins. Moreover, we report histological and transcriptional variations during a wound response, including site differences in ECM composition, cell migration and proliferation, and re‐enactment of distinct developmental programmes. These findings reveal profound regional variation in the mechanisms of tissue repair. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Dissecting Fibroblast Heterogeneity in Health and Fibrotic Disease

PURPOSE OF REVIEW

Fibroblasts, the major cell population in all connective tissues, are best known for their role in depositing and maintaining the extracellular matrix. Recently, numerous specialised functions have been discovered revealing unpredicted fibroblast heterogeneity. We will discuss this heterogeneity, from its origins in development to alterations in fibrotic disease conditions.

RECENT FINDINGS

Advances in lineage tracing and single-cell transcriptional profiling techniques have revealed impressive diversity amongst fibroblasts in a range of organ systems including the skin, lung, kidney and heart. However, there are major challenges in assimilating the findings and understanding their functional significance. Certain fibroblast subsets can make specific contributions to healthy tissue functioning and to fibrotic disease processes; thus, therapeutic manipulation of particular subsets could be clinically beneficial. Here we propose that four key variables determine a fibroblast's phenotype underpinning their enormous heterogeneity: tissue status, regional features, microenvironment and cell state. We review these in different organ systems, highlighting the importance of understanding the divergent fibroblast properties and underlying mechanisms in tissue fibrosis.

Cartilage-like composition of keloid scar extracellular matrix suggests fibroblast mis-differentiation in disease

Following wound damage to the skin, the scarring spectrum is wide-ranging, from a manageable normal scar through to pathological keloids. The question remains whether these fibrotic lesions represent simply a quantitative extreme, or alternatively, whether they are qualitatively distinct. A three-way comparison of the extracellular matrix (ECM) composition of normal skin, normal scar and keloids was performed using quantitative discovery-based proteomics. This approach identified 40 proteins that were significantly altered in keloids compared to normal scars, and strikingly, 23 keloid-unique proteins. The major alterations in keloids, when functionally grouped, showed many changes in proteins involved in ECM assembly and fibrillogenesis, but also a keloid-associated loss of proteases, and a unique cartilage-like composition, which was also evident histologically. The presence of Aggrecan and Collagen II in keloids suggest greater plasticity and mis-differentiation of the constituent cells. This study characterises the ECM of both scar types to a depth previously underappreciated. This thorough molecular description of keloid lesions relative to normal scars is an essential step towards our understanding of this debilitating clinical problem, and how best to treat it.

Spatial and Single-Cell Transcriptional Profiling Identifies Functionally Distinct Human Dermal Fibroblast Subpopulations

Previous studies have shown that mouse dermis is composed of functionally distinct fibroblast lineages. To explore the extent of fibroblast heterogeneity in human skin, we used a combination of comparative spatial transcriptional profiling of human and mouse dermis and single-cell transcriptional profiling of human dermal fibroblasts. We show that there are at least four distinct fibroblast populations in adult human skin, not all of which are spatially segregated. We define markers permitting their isolation and show that although marker expression is lost in culture, different fibroblast subpopulations retain distinct functionality in terms of Wnt signaling, responsiveness to IFN-γ, and ability to support human epidermal reconstitution when introduced into decellularized dermis. These findings suggest that ex vivo expansion or in vivo ablation of specific fibroblast subpopulations may have therapeutic applications in wound healing and diseases characterized by excessive fibrosis.

The Gastric Ganglion of Octopus vulgaris: Preliminary Characterization of Gene- and Putative Neurochemical-Complexity, and the Effect of Aggregata octopiana Digestive Tract Infection on Gene Expression

The gastric ganglion is the largest visceral ganglion in cephalopods. It is connected to the brain and is implicated in regulation of digestive tract functions. Here we have investigated the neurochemical complexity (through in silico gene expression analysis and immunohistochemistry) of the gastric ganglion in Octopus vulgaris and tested whether the expression of a selected number of genes was influenced by the magnitude of digestive tract parasitic infection by Aggregata octopiana. Novel evidence was obtained for putative peptide and non-peptide neurotransmitters in the gastric ganglion: cephalotocin, corticotrophin releasing factor, FMRFamide, gamma amino butyric acid, 5-hydroxytryptamine, molluscan insulin-related peptide 3, peptide PRQFV-amide, and tachykinin-related peptide. Receptors for cholecystokininA and cholecystokininB, and orexin2 were also identified in this context for the first time. We report evidence for acetylcholine, dopamine, noradrenaline, octopamine, small cardioactive peptide related peptide, and receptors for cephalotocin and octopressin, confirming previous publications. The effects of Aggregata observed here extend those previously described by showing effects on the gastric ganglion; in animals with a higher level of infection, genes implicated in inflammation (NFκB, fascin, serpinB10 and the toll-like 3 receptor) increased their relative expression, but TNF-α gene expression was lower as was expression of other genes implicated in oxidative stress (i.e., superoxide dismutase, peroxiredoxin 6, and glutathione peroxidase). Elevated Aggregata levels in the octopuses corresponded to an increase in the expression of the cholecystokininA receptor and the small cardioactive peptide-related peptide. In contrast, we observed decreased relative expression of cephalotocin, dopamine β-hydroxylase, peptide PRQFV-amide, and tachykinin-related peptide genes. A discussion is provided on (i) potential roles of the various molecules in food intake regulation and digestive tract motility control and (ii) the difference in relative gene expression in the gastric ganglion in octopus with relatively high and low parasitic loads and the similarities to changes in the enteric innervation of mammals with digestive tract parasites. Our results provide additional data to the described neurochemical complexity of O. vulgaris gastric ganglion.

Mechanisms of wound closure following acute arm injury in Octopus vulgaris

BACKGROUND

Octopoda utilise their arms for a diverse range of functions, including locomotion, hunting, defence, exploration, reproduction, and grooming. However the natural environment contains numerous threats to the integrity of arms, including predators and prey during capture. Impressively, octopoda are able to close open wounds in an aquatic environment and can fully regenerate arms. The regrowth phase of cephalopod arm regeneration has been grossly described; however, there is little information about the acute local response that occurs following an amputation injury comparable to that which frequently occurs in the wild.

METHODS

Adult Octopus vulgaris caught in the Bay of Naples were anaesthetised, the distal 10 % of an arm was surgically amputated, and wounded tissue was harvested from animals sacrificed at 2, 6, and 24 h post-amputation. The extent of wound closure was quantified, and the cell and tissue dynamics were observed histologically, by electron microscopy, as well as using ultrasound.

RESULTS

Macroscopic, ultrasonic and ultrastructural analyses showed extensive and significant contraction of the wound margins from the earliest time-point, evidenced by tissue puckering. By 6 h post amputation, the wound was 64.0 ± 17.2 % closed compared to 0 h wound area. Wound edge epithelial cells were also seen to be migrating over the wound bed, thus contributing to tissue repair. Temporary protection of the exposed tip in the form of a cellular, non-mucus plug was observed, and cell death was apparent within two hours of injury. At earlier time-points this was apparent in the skin and deeper muscle layers, but ultimately extended to the nerve cord by 24 h.

CONCLUSIONS

This work has revealed that O. vulgaris ecologically relevant amputation wounds are rapidly repaired via numerous mechanisms that are evolutionarily conserved. The findings provide insights into the early processes of repair preparatory to regeneration. The presence of epithelial, chromatophore, vascular, muscle and neural tissue in the arms makes this a particularly interesting system in which to study acute responses to injury and subsequent regeneration.

Infections with benefits

Gastric Helicobacter pylori infection, which has paradoxical effects on human health, alters the immune environment and microbiota.

A Notch in our understanding of vascular disease

Atherosclerosis triggers a decrease in endothelial cell Notch expression, affecting vascular homeostasis and disease susceptibility.

Dendritic cells shaken to the core by pathogenic bacteria

Pathogens induce DNA demethylation in the regulatory regions of immune response genes in dendritic cells.

Early evidence of male sensitivity

Male embryos are more vulnerable to maternal inflammation and associated miscarriage, but preconception low-dose aspirin helps rectify the sex difference in pregnancy loss.

Speedy repair with stabilized β-catenin

CXXC5 inhibition is a novel strategy to stabilize β-catenin and, in turn, accelerate wound healing.

On the origin of fat fibrosis

Perivascular adipocyte progenitors can be tipped to fibrose by growth factor signaling in white adipose tissues.

Behold morphing monocytes at sites of liver damage

Classical proinflammatory monocytes transition to a pro-repair phenotype during repair of sterile tissue damage in the liver.

The 24th annual meeting of the European Tissue Repair Society (ETRS) in Edinburgh, Scotland

From the 10th to 12th of September 2014, in the midst of the Scottish Independence debate, the European Tissue Repair Society descended on Edinburgh for their 24th Annual Meeting. In the beautiful and historic setting of the Royal College of Surgeons of Scotland, Professors David Thomas (Chair), Phil Stephens, Chris Lloyd, and their teams from Cardiff hosted an educational and inspiring program.

Icebergs as unique Lagrangian ecosystems in polar seas

Global warming and its disproportionate impact on polar regions have led to increased iceberg populations. Southern Ocean studies in the northwest Weddell Sea have verified substantial delivery of terrestrial material accompanied by increased primary production and faunal abundance associated with free-drifting icebergs. It is hypothesized that input and utilization of macro- and micronutrients are promoted by conditions unique to free-drifting icebergs, leading to increased production, grazing, and export of organic carbon. In Arctic regions, increased freshwater input from meltwater acts to stratify and stabilize the upper water column. As has been observed in the Southern Ocean, Arctic-region icebergs should drive turbulent upwelling and reduce stratification, potentially leading to increased nitrate delivery to the local ecosystem. Increasing populations of icebergs in polar regions can potentially be important in mediating the drawdown and sequestration of CO(2) and can thus impact the oceanic carbon cycle.

Wound-associated skin fibrosis: mechanisms and treatments based on modulating the inflammatory response

Skin fibrosis, in its mildest form, may present only a minor aesthetic problem, but in the most severe cases it can lead to debilitating pathologies of the skin, for example keloid and hypertrophic scars, and systemic sclerosis. In recent years, extensive basic research aimed at understanding the molecular mechanisms underlying fibrosis has revealed an impressive but baffling number of genes, molecules, and cell types that may contribute to this problem. However, one recurring and consistent theme in these studies is that inflammatory cells and their secreted mediators appear to be leading culprits in activating dermal fibroblasts to become fibrotic. This review will first describe the histology of normal versus fibrotic skin, and will also describe the process of wound repair, a primary cause of skin fibrosis. We will then focus on what is currently known about the molecular mechanisms underlying skin fibrosis, with particular attention paid to how inflammation contributes. Finally, current treatment strategies and emerging therapeutic targets will be discussed.

Phase II evaluation of imatinib mesylate in the treatment of recurrent or persistent epithelial ovarian or primary peritoneal carcinoma: a Gynecologic Oncology Group Study

PURPOSE

This phase II trial assessed the activity and tolerability of an oral dose of imatinib mesylate 400 mg twice daily in patients with recurrent or persistent epithelial ovarian or primary peritoneal carcinoma. The association between the expression of certain markers and clinical outcome was investigated.

PATIENTS AND METHODS

Primary measure of clinical efficacy was progression-free survival (PFS) at 6 months. Mutational analysis of KIT, immunohistochemistry (IHC) and enzyme-linked immunosorbent assay for markers (KIT, platelet-derived growth factor [PDGF] receptor [-R], AKT2, phosphorylated AKT [p-AKT], stem cell factor [SCF], and PDGF) were performed.

RESULTS

Fifty-six eligible patients were evaluated. Nine patients were progression free for at least 6 months including one complete responder. The median PFS and survival were 2 and 16 months, respectively. The most common grade 3 and 4 toxicities were neutropenia, GI, dermatologic effects, pain, and electrolyte disturbances. At least one target of imatinib (KIT, PDGFR-alpha, or PDGFR-beta) was expressed in all tumors, and most tumors expressed all three receptors. Higher expression of p-AKT and PDGFR-beta were associated with shorter PFS, and higher IHC scores (% immunopositive cells x staining intensity) of SCF and p-AKT were associated with decreased overall survival. No sequence mutations were detected in the KIT gene. Higher pretreatment plasma concentrations of PDGF-AB, PDGF-BB, and vascular endothelial growth factor (VEGF) were individually associated with shorter PFS and survival.

CONCLUSION

Imatinib mesylate was well tolerated but had minimal single-agent activity in patients with recurrent ovarian or primary peritoneal carcinoma. No marker was identified that would predict activity of imatinib; however, tumor p-AKT and plasma VEGF levels were associated with poor outcome.

Downregulation of XIAP expression in ovarian cancer cells induces cell death in vitro and in vivo

A hallmark of cancer cells is an ability to evade apoptosis. Overexpression and/or activating mutations of prosurvival molecules such as the X-linked inhibitor of apoptosis (XIAP) contribute to this inappropriate cell survival. Our objectives were to investigate the effects of downregulation of XIAP in ovarian cancer cells in vitro and in vivo using the clinical candidate antisense oligonucleotide against XIAP, AEG35156 (AS XIAP). Three ovarian cancer cell lines were transfected with AS XIAP in vitro, and the effects on cell survival were assessed. Downregulation of XIAP resulted in significant apoptosis. To investigate the in vivo efficacy of AS XIAP, CD-1 nude mice were xenografted intraperitoneally with A2780-cp cells, treated with intraperitoneal AS XIAP and evaluated for survival time and tumor histology. Mice treated with 10 mg/kg/day AS XIAP showed a significant improvement in survival time compared to animals treated with control oligonucleotides. Histological analysis of the tumors showed significantly fewer viable cells in the AS XIAP-treated tumors. Downregulation of XIAP expression in ovarian cancer cells resulted in apoptosis in vitro and a prolonged survival time of ovarian cancer-bearing mice, which indicate that XIAP may be a valuable therapeutic target in ovarian cancers, and supports the ongoing clinical investigation of AEG35156.

Molecular mechanisms linking wound inflammation and fibrosis: knockdown of osteopontin leads to rapid repair and reduced scarring

Previous studies of tissue repair have revealed osteopontin (OPN) to be up-regulated in association with the wound inflammatory response. We hypothesize that OPN may contribute to inflammation-associated fibrosis. In a series of in vitro and in vivo studies, we analyze the effects of blocking OPN expression at the wound, and determine which inflammatory cells, and which paracrine factors from these cells, may be responsible for triggering OPN expression in wound fibroblasts. Delivery of OPN antisense oligodeoxynucleotides into mouse skin wounds by release from Pluronic gel decreases OPN protein levels at the wound and results in accelerated healing and reduced granulation tissue formation and scarring. To identify which leukocytic lineages may be responsible for OPN expression, we cultured fibroblasts in macrophage-, neutrophil-, or mast cell-conditioned media (CM), and found that macrophage- and mast cell-secreted factors, specifically platelet-derived growth factor (PDGF), induced fibroblast OPN expression. Correspondingly, Gleevec, which blocks PDGF receptor signaling, and PDGF-Rbeta-neutralizing antibodies, inhibited OPN induction by macrophage-CM. These studies indicate that inflammation-triggered expression of OPN both hinders the rate of repair and contributes to wound fibrosis. Thus, OPN and PDGF are potential targets for therapeutic modulation of skin repair to improve healing rate and quality.

AKT mediates the pro-survival effects of KIT in ovarian cancer cells and is a determinant of sensitivity to imatinib mesylate

OBJECTIVES

Little is known about the function of KIT in ovarian cancer cells, despite its expression in most tumors and extensive speculation on the therapeutic value of its inhibition. This study investigated the consequences of KIT signaling on ovarian cancer cell proliferation and survival and evaluated the molecular basis of sensitivity to imatinib mesylate.

METHODS

Ovarian cancer cells were treated with KIT ligand (KL), the KIT neutralizing antibody ACK2, or imatinib mesylate and analyzed for changes in proliferation and chemosensitivity. Cells were analyzed for KIT, PDGF-R and AKT expression, which were then correlated with imatinib sensitivity. The importance of AKT in determining the sensitivity of cells to the drug was further evaluated by comparing the effects of, and co-treating with, imatinib and wortmannin.

RESULTS

Proliferation was unaffected by modulations to KIT signaling; however, pro-survival effects were observed. Specifically, KL increased and ACK2 decreased cisplatin resistance. Similarly, imatinib resulted in significant sensitization to cell death, albeit to varying degrees, in the five cell lines tested. All cell lines expressed at least one of the target molecules for imatinib, but responsiveness did not rely upon the expression of any one specific receptor. However, an inverse relationship between pAKT and imatinib sensitivity was identified. Decreasing pAKT with wortmannin did not achieve the equivalent cell killing as imatinib, but wortmannin did increase sensitivity to imatinib treatment.

CONCLUSIONS

This study demonstrates that KIT transduces anti-apoptotic signals and its inhibition with imatinib may represent a valuable therapeutic strategy for sensitizing chemoresistant ovarian cancer. pAKT may provide a mechanism of resistance to imatinib that correspondingly could serve as a predictor of sensitivity to treatment.

Small threat and contraband detection with TNA-based systems

The detection of small threats, such as explosives, drugs, and chemical weapons, concealed or encased in surrounding material, is a major concern in areas from security checkpoints to UneXploded Ordnance (UXO) clearance. Techniques such as X-ray and trace detection are often ineffectual in these applications. Thermal neutron analysis (TNA) provides an effective method for detecting concealed threats. This paper shows the effectiveness of Ancore's SPEDS, based on TNA, in detecting concealed liquid threats and differentiating live from inert mortar shells.

Models of ovarian cancer--are we there yet?

Ovarian cancer is the most lethal of all gynecological cancers and arises most commonly from the surface epithelium. Successful clinical management of patients with epithelial ovarian cancer is limited by the lack of a reliable and specific method for early detection, and the frequent recurrence of chemoresistant disease. Experimental models are of crucial importance not only to understand the biological and genetic factors that influence the phenotypic characteristics of the disease but also to utilize as a basis for developing rational intervention strategies. Ovarian cancer cell lines derived from ascites or primary ovarian tumors have been used extensively and can be very effective for studying the processes controlling growth regulation and chemosensitivity or evaluating novel therapeutics, both in vitro and in xenograft models. While our limited knowledge of the initiating events of ovarian cancer has restricted the development of models in which the early pathogenic events can be studied, recent advances in the ability to manipulate gene expression in ovarian surface epithelial cells in vitro and in vivo have begun to provide insights into the molecular changes that may contribute to the development of ovarian cancer. This review highlights the strengths and weaknesses of some of the current models of ovarian cancer, with special consideration of the recent progress in modeling ovarian cancer using genetically engineered mice.

Characterization of intraperitoneal, orthotopic, and metastatic xenograft models of human ovarian cancer

Improvement of ovarian cancer patient outcome requires well-characterized animal models in which to evaluate novel therapeutics. Xenograft models are frequently used, but with little discussion of disease histology. The objectives of this study were to inject 11 ovarian cancer cell lines intraperitoneally (ip), and a subset intrabursally (ib; orthotopic), into nude mice and to analyze the resulting pathologies. Eight of 11 lines injected ip formed tumors within 3 months at variable rates with the following histological subtype distribution: one endometrioid, one serous, one clear cell, and five undifferentiated. Only mice injected with A2780-cp cells presented with ovarian-specific metastases (11 of 88), and the survival time of these animals was significantly shorter, which may be attributed to the higher proliferation rate as determined by Ki67 positivity. Additional analysis of the influence of the ovarian microenvironment on cell characteristics was conducted with ib injection of two cell lines (OVCA 429 and ES-2). The site of injection did not affect the tumor histology, the effect on proliferation was cell-type dependent, and the tumor take rate (cell survival) was negatively affected for OVCA 429 cells. The animal models described herein represent histologically distinct models of both early and late stage ovarian cancer useful for evaluation of therapeutics.

Inhibin resistance is associated with aggressive tumorigenicity of ovarian cancer cells

Malignant ovarian epithelial tumors have been shown to have decreased inhibin production relative to activin production compared with normal ovarian surface epithelial (OSE) cells and nonmalignant ovarian tumors. Activin stimulates proliferation of many ovarian cancer cell lines. Inhibin antagonizes the action of activin, and inhibin-deficient mice develop gonadal tumors, suggesting that inhibin may be a tumor suppressor. However, its effects on OSE and ovarian cancer cells are unknown. We hypothesize that activin and inhibin are important regulators of biological activity in ovarian cancers. We found that inhibin A decreased murine OSE proliferation, whereas activin A had no effect. Activin A increased the proliferation of four of eight ovarian cancer cell lines (SKOV3, OCC1, OVCAR3, and A2780-s). Inhibin A decreased the proliferation of SKOV3, A2780-s, and OVCAR3 but had no effect on OCC1, ES-2, HEY, A2780-cp, and OVCA429 cells. When injected into nude mice, the inhibin-resistant cancer cell lines resulted in shorter survival time compared with the inhibin-responsive cells. Further investigations on SKOV3 and OCC1 cells showed that activin A increased invasion through Matrigel. Inhibin A decreased both basal and activin-induced proliferation and invasion of SKOV3 but had no effect on OCC1 cells. Reverse transcription-PCR analyses showed that the SKOV3 and OCC1 cells produced activin, but only SKOV3 produced inhibin. Analysis of the activin/inhibin signaling pathways indicated that Smad anchor for receptor activation was elevated in SKOV3 and OCC1 cells and that an up-regulation of the activin receptor expression may explain the inhibin resistance of OCC1 cells. Our results suggest that activin responsiveness may be gained during transformation of OSE cells and that inhibin resistance may contribute to the aggressive behavior of ovarian cancer cells.

Inhibin Resistance Is Associated with Aggressive Tumorigenicity of Ovarian Cancer Cells

Malignant ovarian epithelial tumors have been shown to have decreased inhibin production relative to activin production compared with normal ovarian surface epithelial (OSE) cells and nonmalignant ovarian tumors. Activin stimulates proliferation of many ovarian cancer cell lines. Inhibin antagonizes the action of activin, and inhibin-deficient mice develop gonadal tumors, suggesting that inhibin may be a tumor suppressor. However, its effects on OSE and ovarian cancer cells are unknown. We hypothesize that activin and inhibin are important regulators of biological activity in ovarian cancers. We found that inhibin A decreased murine OSE proliferation, whereas activin A had no effect. Activin A increased the proliferation of four of eight ovarian cancer cell lines (SKOV3, OCC1, OVCAR3, and A2780-s). Inhibin A decreased the proliferation of SKOV3, A2780-s, and OVCAR3 but had no effect on OCC1, ES-2, HEY, A2780-cp, and OVCA429 cells. When injected into nude mice, the inhibin-resistant cancer cell lines resulted in shorter survival time compared with the inhibin-responsive cells. Further investigations on SKOV3 and OCC1 cells showed that activin A increased invasion through Matrigel. Inhibin A decreased both basal and activin-induced proliferation and invasion of SKOV3 but had no effect on OCC1 cells. Reverse transcription-PCR analyses showed that the SKOV3 and OCC1 cells produced activin, but only SKOV3 produced inhibin. Analysis of the activin/inhibin signaling pathways indicated that Smad anchor for receptor activation was elevated in SKOV3 and OCC1 cells and that an up-regulation of the activin receptor expression may explain the inhibin resistance of OCC1 cells. Our results suggest that activin responsiveness may be gained during transformation of OSE cells and that inhibin resistance may contribute to the aggressive behavior of ovarian cancer cells.

Endobronchial ultrasound to assess airway wall thickening: validation in vitro and in vivo

Endobronchial ultrasound (EBUS) allows identification of airway wall structures and could potentially be utilised for in vivo studies of airway thickening in asthma. The present study investigated whether inflation of the fluid-filled balloon sheath over the transducer (necessary to provide sonic coupling with the airway wall) influenced in vitro measurements. In vivo comparability of EBUS with high resolution computed tomography scanning (HRCT), an established method for measuring wall thickness, was determined in control subjects. The airway diameter and wall thickness were studied using EBUS in 24 cartilaginous airways obtained from four sheep, before and after balloon sheath inflation during immersion in saline. To assess EBUS versus HRCT comparability of airway measures in vivo, 12 control subjects underwent imaging of the posterior basal bronchus of the right lower lobe by both techniques. Intra- and interobserver agreement were also assessed. Results with and without the balloon sheath gave comparable measures of airway internal diameter and wall thickness in vitro. Statistical analysis showed agreement between EBUS and HRCT, and intra- and interobserver variability in vivo. The current study concludes that endobronchial ultrasound, which does not present a radiation risk, could be utilised in the in vivo study of cartilaginous airway wall remodelling in respiratory diseases, such as asthma.

Animal models of ovarian cancer

Ovarian cancer is the most lethal of all of the gynecological cancers and can arise from any cell type of the ovary, including germ cells, granulosa or stromal cells. However, the majority of ovarian cancers arise from the surface epithelium, a single layer of cells that covers the surface of the ovary. The lack of a reliable and specific method for the early detection of epithelial ovarian cancer results in diagnosis occurring most commonly at late clinical stages, when treatment is less effective. In part, the deficiency in diagnostic tools is due to the lack of markers for the detection of preneoplastic or early neoplastic changes in the epithelial cells, which reflects our rather poor understanding of this process. Animal models which accurately represent the cellular and molecular changes associated with the initiation and progression of human ovarian cancer have significant potential to facilitate the development of better methods for the early detection and treatment of ovarian cancer. This review describes some of the experimental animal models of ovarian tumorigenesis that have been reported, including those involving specific reproductive factors and environmental toxins. Consideration has also been given to the recent progress in modeling ovarian cancer using genetically engineered mice.

Cyclic AMP in ovarian cancer cells both inhibits proliferation and increases c-KIT expression

C-KIT encodes a tyrosine kinase receptor (KIT) that, when activated by its ligand (KL), stimulates proliferation, differentiation, migration, and survival. Greater than 70% of epithelial ovarian cancers coexpress c-KIT and KL. C-KIT and KL expression levels have been shown to be up-regulated by cAMP in some cell types. Additionally, cAMP is well-recognized for its anti-proliferative effects in cancer cells. The goal of these experiments was to investigate these seemingly contradictory consequences of cAMP treatment by: (1) confirming the growth inhibitory actions of cAMP on ovarian cancer cells; (2) investigating the ability of cAMP to affect c-KIT and KL expression in these cells; and (3) examining the possible role of endogenous and/or cAMP-regulated c-KIT and KL expression in ovarian cancer cell proliferation. HEY cells, an ovarian cancer cell line which expresses c-KIT and KL, were treated with dibutyryl cyclic AMP (dbcAMP), 8-bromo-cAMP, and cholera toxin over a range of concentrations. With all treatments, stimulation of cAMP signaling caused a dose-dependent inhibition of HEY cell proliferation by up to 40, 62, and 38%, respectively. This inhibition of proliferation correlated with a dose-dependent increase in c-KIT mRNA expression, yielding 4- to 7-fold elevations in transcript abundance; there were no changes in steady-state levels of KL transcripts. In order to determine whether KIT expression/activity was responsible for the observed decrease in proliferation, dbcAMP-treated HEY cells were exposed either to anti-KIT neutralizing antibodies or to the KIT inhibitor STI571. These experiments demonstrated that KIT inhibition did not alter the growth rate of cells or reverse the dbcAMP-induced inhibition of proliferation. These results suggest that cAMP signaling pathways regulate both cell proliferation and c-KIT expression in ovarian cancer cells; however, KIT is not assuming its well-established role as a growth factor.

Role of alpha-MSH in the regulation of consummatory behavior: immunohistochemical evidence

Central injection of alpha-melanocyte-stimulating hormone (alpha-MSH) decreases food intake, suggesting a role for this peptide in the mediation of satiety. Inasmuch as alpha-MSH also supports the development of taste aversions under certain conditions, the nature of its influence on ingestive behavior, i.e., whether it is related to satiety or aversion, remains unclear. In the present studies, we used immunostaining, including that for c-Fos as a marker of neuronal activation, to further substantiate the physiological role for alpha-MSH in the regulation of consummatory behavior. We found that an increase in activation of alpha-MSH neurons in the arcuate nucleus coincided with meal termination. Administration of powerful aversive agents, LiCl and CuSO(4), did not stimulate alpha-MSH cells but did induce pronounced activation of oxytocin (OT) and vasopressin (VP) neurons, the final components of circuitry mediating aversion. We observed fewer Fos-positive OT/VP neurons after alpha-MSH injection into the lateral ventricle or into the hypothalamic paraventricular nucleus, treatments that cause mild or no aversion, respectively. The degree of activation of OT/VP neurons paralleled the magnitude of aversive response to a given treatment. Our data support the hypothesis that, in the arcuate nucleus, alpha-MSH acts as a satiety mediator independent from aversion-related mechanisms.

Acute toxicity of five sediment-associated metals, individually and in a mixture, to the estuarine meiobenthic harpacticoid copepod Amphiascus tenuiremis

The acute effects of many individual, seawater-solubilized metals on meiobenthic copepods and nematodes are well known. In sediments, however, metals most often occur as mixtures, and it is not known whether such mixtures exhibit simple additive toxicity to meiobenthos. The estuarine meiobenthic copepod Amphiascus tenuiremis was tested in four acute (96-h) sediment bioassays to determine sediment and pore-water LC50s for single-metal exposures to copper (Cu), lead (Pb), nickel (Ni) and zinc (Zn). Laboratory-cultured copepods were exposed to clean 98% silt:clay sediments spiked with metal chloride solutions to yield five exposure concentrations plus a control. Trimmed Spearman-Karber analysis gave sediment 96-h LC50 values of 4.4 mumole Cu/g, 5.7 mumole Ni/g, 11.9 mumole Pb/g, 10.3 mumole Zn/g, and pore-water 96-h LC50 values of 2 mumole/l, 11.7 mumole/l, and 5.7 mumole/l for Cu, Ni, and Zn, respectively. Male survival after exposure to Cu, Pb, and Ni was significantly less than female survival (alpha = 0.05). Toxicity of a combined USEPA priority metal mixture to A. tenuiremis was assessed using sediment spiked equitoxically with Cd, Cu, Ni, Pb, and Zn. The sum toxic unit that produced a median lethal dose was 0.72. The mixture had a significantly greater than additive effect on A. tenuiremis survival, with the mixture being 1.4x more toxic than that expected by simple additivity.

Nocistatin inhibits food intake in rats

Nocistatin, a product of the same precursor as nociceptin/orphanin FQ (N/OFQ), has been shown to antagonize effects of N/OFQ. N/OFQ stimulates feeding, most probably by inhibiting activation of neurons containing oxytocin (OT) and vasopressin (VP), peptides considered as satiety factors, and implicated in the development of conditioned taste aversion (CTA). The present study was designed to investigate whether intracerebroventricularly (ICV) injected nocistatin (a) affects deprivation- and N/OFQ-induced feeding, (b) causes CTA, and (c) induces activation of hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei, as well as OT and VP neurons present in these regions. C-Fos immunohistochemistry was used as a marker of cellular activation. Nocistatin (1-3 nmol) significantly reduced food intake in deprived rats during the first and second hour post-injection. Doses of 1-3 nmol suppressed N/OFQ-induced feeding. Nocistatin at the highest (3 nmol) dose did not cause CTA. It also did not affect activation of the PVN or SON. In nocistatin-treated animals, the percentage of Fos-positive OT and VP neurons was similar to controls. We conclude that nocistatin antagonizes the influence of N/OFQ on feeding and suppresses deprivation-induced food consumption through mechanisms other than aversion. Nocistatin does not, however, activate the PVN or SON. It does not exert its effects via VP or OT neurons.

Expression of glucosamine trisaccharides on the rat uterine surface is altered by clomiphene citrate

We have studied histochemically the effects of clomiphene citrate on the expression of oligosacchrides on the apical plasma membrane of uterine epithelial cells using the lectin Phytolacca americana. Ovariectomized sexually mature rats were given a single injection of either clomiphene in two concentrations or estradiol 17 beta or progesterone and were killed 24 hr later. Uterine tissue was labeled with Phytolacca americana conjugated with avidin and subsequently labeled with biotinalyted ferritin and prepared for transmission electron microscopy. Our results indicate that clomiphene and to a lesser degree progesterone significantly increased lectin binding. However, the increase was not as large as that observed with a single dose of estrodiol 17 beta. When the proportion of lectin positivity in relation to total membrane length was analyzed, treatment with clomiphene and progesterone did not have significantly different effects. Low dose clomiphene did not have a significant effect as compared with controls. Our data show that clomiphene has a dose-dependent adverse effect on lectin binding as compared with ovarian hormones. We suggest that these effects contribute to low pregnancy rates with clomiphene use.

Junctional plaque proteins shift to the apical surface of uterine epithelial cells during early pregnancy in the rat

Antibodies against the cytoplasmic plaque molecules, plectin and plakoglobin, and cytokeratin, the molecular component of intermediate filaments (IFs), were used to examine the distribution of these molecules in rat uterine epithelial cells during early pregnancy including the period of blastocyst implantation. On day 1 of pregnancy plectin was detected in concentrated bands along the apical and basal plasma membranes, and diffusely throughout the cytoplasm. Plakoglobin was found along the entire lateral plasma membrane on day 1. By day 6, the time of blastocyst implantation, plectin was localised along the apical and basal membranes and reduced in the basal cytoplasm, and plakoglobin was seen exclusively at the apical-most quarter of the lateral plasma membrane. Cytokeratin was detected throughout the cytoplasm on day 1, but by day 6, was localised to the apical region of the cytoplasm only. These results show a redistribution of plectin, plakoglobin and cytokeratin away from the basal region of the uterine epithelial cells. The change in distribution of these molecules may contribute to the adhesion of the blastocyst to the apical and lateral surfaces of uterine epithelial cells and the subsequent detachment of the uterine epithelium from the basal lamina.

Alterations in distribution of actin binding proteins in uterine stromal cells during decidualization in the rat

Immunohistochemistry was used to investigate the involvement of the actin-associated binding proteins, tropomyosin, alpha-actinin and gelsolin with the formation of the decidual cell reaction during early pregnancy in the rat. Tropomyosin was present in the uterine myometrium, but absent from the both decidual and non-decidual stromal cells. alpha-Actinin was absent from non-decidual stromal cells, but present in decidual cells. Gelsolin was present in non-decidual cells close to the uterine stroma as well as in transformed decidual cells. Both gelsolin and alpha-actinin were concentrated around the periphery of the cell. It is proposed that these actin-binding proteins may be involved with the cellular transformations associated with decidualization.

Perceived sources of occupational stress in general dental practitioners

AIM

To evaluate levels of occupational stress in general dental practitioners (GDPs) and compare them with those reported by Cooper et al. (1987).

DESIGN/SETTING

Postal questionnaire in England and Wales.

SUBJECTS

A sample of 1007 GDPs was chosen from the Dental Register.

MAIN OUTCOME MEASURES

30 separate stressors were scored on a 5-point scale. Summated scores within time-, job-, income-, staff- and patient-related categories were submitted to analysis of variance by sex, type of practice, years since qualification and geographic location.

RESULTS

823 questionnaires were returned (82%) of which 667 were from practising GDPs (63% male, 26% female, 1% undetermined) working full- (87%) or part- (13%) time in NHS (61%), private (8%), mixed (26%), or community (5%) practice. In general, problems associated with time management were the most stressful. The highest ranked individual stressors were 'running behind schedule' (percentage responding with scores 4 or 5 = 61.9, 95% confidence intervals = 58.2-65.6), followed by 'coping with difficult or uncooperative patients' (58.2, 54.5-61.9) and the 'working constraints set by the NHS' (57.5, 53.8-61.2). Differences in levels of reported stress (P < 0.05) were observed for at least one group category of stressor between practitioners with different types of practice, between males and females, by geographical area (north against south) and by the length of time since qualification.

CONCLUSIONS

The results indicate that GDPs now rank factors related to time management as major job stressors, with an apparently dramatic elevation of 'NHS working constraints' to a top-ranking stressor since 1986.

Pan-cadherin concentrates apically in uterine epithelial cells during uterine closure in the rat

The ubiquitous cadherin probe, pan-cadherin was used to study changes in the distribution of cadherins in the plasma membrane of rat uterine epithelial cells during early pregnancy when the uterine lumen closes down. A major reorganisation of cadherin expression was observed to occur in uterine epithelial cells between days 1 and 6 of pregnancy with a clear shift in molecular distribution from a basal location on day 1 to a distinctly and almost exclusively apical distribution by day 6 of pregnancy when the blastocyst is attached. We suggest these results indicate participation of this molecule in closure of the uterine lumen, a phenomenon well-known to occur in the rat uterus during early pregnancy and in which apical surfaces of opposing uterine epithelial cells cohere.

Leucocyte binding to the uterine epithelial cell surface during lectin-induced decidualization

Intra-uterine injection of the lectin Concanavalin A (ConA) on day 5 of pseudopregnancy induced a rapid and persistent infiltration of leucocytes into the rat uterine stroma. Although the infiltration of leucocytes was seen along the entire length of the uterine horn, areas of stromal oedema, indicative of decidualization (as indicated by a positive Pontamine Sky Blue reaction), were only associated with regions in which leucocytes had crossed the uterine epithelium and were present in the uterine lumen. Ultrastructural evaluation of the interaction of the luminal leucocytes with the apical surface of the uterine epithelium appeared strikingly similar to that of the blastocyst and the uterine epithelium during normal implantation. It is proposed that leucocytes, induced by ConA, may initiate a decidual response in a manner analogous to that of the blastocyst through surface epithelial interaction.

Actin-binding proteins undergo major alterations during the plasma membrane transformation in uterine epithelial cells

BACKGROUND

The apical surface of uterine epithelial cells undergoes a dramatic transformation during early pregnancy. Previous studies have shown that cytoskeletal actin microfilaments are associated with this transformation, but little is known of the role played by actin-binding proteins or which of the many described in other cell types are present in uterine epithelial cells.

METHODS

Immunohistochemical staining using monoclonal antibodies raised against four different actin-binding proteins (alpha-actinin, tropomyosin, gelsolin, and vinculin) was used to study the changing distribution of these proteins in uterine epithelium during early pregnancy in the rat.

RESULTS

Findings indicated the presence of all four of the actin-binding proteins in the uterine epithelium. The distribution of tropomyosin remained unchanged over the period of early pregnancy. Gelsolin and alpha-actinin displayed similarity in distribution. Day 1 showed an apicobasal localisation of reaction product, which by day 6 of pregnancy had concentrated into a thick band across the luminal surface of the cells. Vinculin staining was a diffuse band at the level of the basal plasma membrane at day 1 and became a diffuse faint band across the apical part of the cells on day 6.

CONCLUSIONS

This study confirms the presence of actin-binding proteins in uterine epithelial cells, and these findings are discussed in light of known ultrastructural alterations in the uterine epithelium during early pregnancy. Elucidation of the role of the actin-based cytoskeleton in the uterine epithelium may further our understanding of the dynamics of this unique environment that allows the implantation of a blastocyst.