A median fin derived from the lateral plate mesoderm and the origin of paired fins.

The development of paired appendages was a key innovation during evolution and facilitated the aquatic to terrestrial transition of vertebrates. Largely derived from the lateral plate mesoderm (LPM), one hypothesis for the evolution of paired fins invokes derivation from unpaired median fins via a pair of lateral fin folds located between pectoral and pelvic fin territories1. Whilst unpaired and paired fins exhibit similar structural and molecular characteristics, no definitive evidence exists for paired lateral fin folds in larvae or adults of any extant or extinct species. As unpaired fin core components are regarded as exclusively derived from paraxial mesoderm, any transition presumes both co-option of a fin developmental programme to the LPM and bilateral duplication2. Here, we identify that the larval zebrafish unpaired pre-anal fin fold (PAFF) is derived from the LPM and thus may represent a developmental intermediate between median and paired fins. We trace the contribution of LPM to the PAFF in both cyclostomes and gnathostomes, supporting the notion that this is an ancient trait of vertebrates. Finally, we observe that the PAFF can be bifurcated by increasing bone morphogenetic protein signalling, generating LPM-derived paired fin folds. Our work provides evidence that lateral fin folds may have existed as embryonic anlage for elaboration to paired fins.

Cell coupling compensates for changes in single-cell Her6 dynamics and provides phenotypic robustness.

This paper investigates the effect of altering the protein expression dynamics of the bHLH transcription factor Her6 at the single-cell level in the embryonic zebrafish telencephalon. Using a homozygote endogenous Her6:Venus reporter and 4D single-cell tracking, we show that Her6 oscillates in neural telencephalic progenitors and that the fusion of protein destabilisation (PEST) domain alters its expression dynamics, causing most cells to downregulate Her6 prematurely. However, counterintuitively, oscillatory cells increase, with some expressing Her6 at high levels, resulting in increased heterogeneity of Her6 expression in the population. These tissue-level changes appear to be an emergent property of coupling between single-cells, as revealed by experimentally disrupting Notch signalling and by computationally modelling alterations in Her6 protein stability. Despite the profound differences in the single-cell Her6 dynamics, the size of the telencephalon is only transiently altered and differentiation markers do not exhibit significant differences early on; however, a small increase is observed at later developmental stages. Our study suggests that cell coupling provides a compensation strategy, whereby an almost normal phenotype is maintained even though single-cell gene expression dynamics are abnormal, granting phenotypic robustness.

Sequential and additive expression of miR-9 precursors control timing of neurogenesis.

MicroRNAs (miRs) have an important role in tuning dynamic gene expression. However, the mechanism by which they are quantitatively controlled is unknown. We show that the amount of mature miR-9, a key regulator of neuronal development, increases during zebrafish neurogenesis in a sharp stepwise manner. We characterize the spatiotemporal profile of seven distinct microRNA primary transcripts (pri-mir)-9s that produce the same mature miR-9 and show that they are sequentially expressed during hindbrain neurogenesis. Expression of late-onset pri-mir-9-1 is added on to, rather than replacing, the expression of early onset pri-mir-9-4 and -9-5 in single cells. CRISPR/Cas9 mutation of the late-onset pri-mir-9-1 prevents the developmental increase of mature miR-9, reduces late neuronal differentiation and fails to downregulate Her6 at late stages. Mathematical modelling shows that an adaptive network containing Her6 is insensitive to linear increases in miR-9 but responds to stepwise increases of miR-9. We suggest that a sharp stepwise increase of mature miR-9 is created by sequential and additive temporal activation of distinct loci. This may be a strategy to overcome adaptation and facilitate a transition of Her6 to a new dynamic regime or steady state.

Dynamic properties of noise and Her6 levels are optimized by miR-9, allowing the decoding of the Her6 oscillator.

Noise is prevalent in biology and has been widely quantified using snapshot measurements. This static view obscures our understanding of dynamic noise properties and how these affect gene expression and cell state transitions. Using a CRISPR/Cas9 Zebrafish her6::Venus reporter combined with mathematical and in vivo experimentation, we explore how noise affects the protein dynamics of Her6, a basic helix-loop-helix transcriptional repressor. During neurogenesis, Her6 expression transitions from fluctuating to oscillatory at single-cell level. We identify that absence of miR-9 input generates high-frequency noise in Her6 traces, inhibits the transition to oscillatory protein expression and prevents the downregulation of Her6. Together, these impair the upregulation of downstream targets and cells accumulate in a normally transitory state where progenitor and early differentiation markers are co-expressed. Computational modelling and double smFISH of her6 and the early neurogenesis marker, elavl3, suggest that the change in Her6 dynamics precedes the downregulation in Her6 levels. This sheds light onto the order of events at the moment of cell state transition and how this is influenced by the dynamic properties of noise. Our results suggest that Her/Hes oscillations, facilitated by dynamic noise optimization by miR-9, endow progenitor cells with the ability to make a cell state transition.

Zebrafish IL-4-like Cytokines and IL-10 Suppress Inflammation but Only IL-10 Is Essential for Gill Homeostasis.

Mucosal surfaces such as fish gills interface between the organism and the external environment and as such are major sites of foreign Ag encounter. In the gills, the balance between inflammatory responses to waterborne pathogens and regulatory responses toward commensal microbes is critical for effective barrier function and overall fish health. In mammals, IL-4 and IL-13 in concert with IL-10 are essential for balancing immune responses to pathogens and suppressing inflammation. Although considerable progress has been made in the field of fish immunology in recent years, whether the fish counterparts of these key mammalian cytokines perform similar roles is still an open question. In this study, we have generated IL-4/13A and IL-4/13B mutant zebrafish (Danio rerio) and, together with an existing IL-10 mutant line, characterized the consequences of loss of function of these cytokines. We demonstrate that IL-4/13A and IL-4/13B are required for the maintenance of a Th2-like phenotype in the gills and the suppression of type 1 immune responses. As in mammals, IL-10 appears to have a more striking anti-inflammatory function than IL-4-like cytokines and is essential for gill homeostasis. Thus, both IL-4/13 and IL-10 paralogs in zebrafish exhibit aspects of conserved function with their mammalian counterparts.

No. 164-Consensus Guidelines for the Management of Chronic Pelvic Pain.

OBJECTIVE: To improve the understanding of chronic pelvic pain (CPP) and to provide evidence-based guidelines of value to primary care health professionals, general obstetricians and gynaecologists, and those who specialize in chronic pain. BURDEN OF SUFFERING: CPP is a common, debilitating condition affecting women. It accounts for substantial personal suffering and health care expenditure for interventions, including multiple consultations and medical and surgical therapies. Because the underlying pathophysiology of this complex condition is poorly understood, these treatments have met with variable success rates. OUTCOMES: Effectiveness of diagnostic and therapeutic options, including assessment of myofascial dysfunction, multidisciplinary care, a rehabilitation model that emphasizes achieving higher function with some pain rather than a cure, and appropriate use of opiates for the chronic pain state. EVIDENCE: Medline and the Cochrane Database from 1982 to 2004 were searched for articles in English on subjects related to CPP, including acute care management, myofascial dysfunction, and medical and surgical therapeutic options. The committee reviewed the literature and available data from a needs assessment of subjects with CPP, using a consensus approach to develop recommendations. VALUES: The quality of the evidence was rated using the criteria described in the Report of the Canadian Task Force on the Periodic Health Examination. Recommendations for practice were ranked according to the method described in that report (Table 1). RECOMMENDATIONS: The recommendations are directed to the following areas: (a) an understanding of the needs of women with CPP; (b) general clinical assessment; (c) practical assessment of pain levels; (d) myofascial pain; (e) medications and surgical procedures; (d) principles of opiate management; (f) increased use of magnetic resonance imaging (MRI); (g) documentation of the surgically observed extent of disease; (h) alternative therapies; (i) access to multidisciplinary care models that have components of physical therapy (such as exercise and posture) and psychology (such as cognitive-behavioural therapy), along with other medical disciplines, such as gynaecology and anesthesia; G) increased attention to CPP in the training of health care professionals; and (k) increased attention to CPP in formal, high-calibre research. The committee recommends that provincial ministries of health pursue the creation of multidisciplinary teams to manage the condition.

No 164 - Directive clinique de consensus pour la prise en charge de la douleur pelvienne chronique.

OBJECTIF: Améliorer La compréhension de la douleur pelvienne chronique (DPC) et fournir des directives cliniques factuelles qui bénéficieront aux fournisseurs de soins de santé primaires, aux obstétriciens-gynécologues et aux spécialistes de la douleur chronique. FARDEAU DE LA SOUFFRANCE: La DPC est une pathologie débilitante courante qui affecte les femmes. Elle est à l'origine d'importantes souffrances personnelles et de dépenses de santé considérables associées aux interventions, dont de multiples consultations et un grand nombre de traitements médicaux et chirurgicaux. Puisque la pathophysiologie sous-jacente de cet état pathologique complexe est mal comprise, ces traitements n'ont obtenu que des taux de réussite variables. ISSUES: Efficacité des options diagnostiques et thérapeutiques (y compris l'évaluation du dysfonctionnement myofascial); soins multidisciplinaires; un modèle de réadaptation mettant l'accent sur l'obtention d'un fonctionnement supérieur malgré la présence d'une certaine douleur (plutôt que de chercher à obtenir une guérison totale); et utilisation appropriée des opiacés pour le soulagement de la douleur chronique. PREUVES: Des recherches ont été menées dans Medline et la base de données Cochrane en vue d'en tirer les articles de langue anglaise, publiés entre 1982 et 2004, portant sur des sujets liés à la DPC, dont la gestion des soins actifs, le dysfonctionnement myofascial et les options thérapeutiques médicales et chirurgicales. Les membres du comité ont analysé la littérature pertinente, ainsi que les données disponibles tirées d'une évaluation des besoins des personnes présentant une DPC; ils ont fait appel à une approche de consensus pour l'élaboration des recommandations. VALEURS: La qualité des résultats a été évaluée au moyen des critères décrits dans le rapport du Groupe d'étude canadien sur l'examen médical périodique. Les recommandations visant la pratique ont été classées conformément à la méthode décrite dans ce rapport (Tableau 1). RECOMMANDATIONS: Les recommandations visent ce qui suit : (a) compréhension des besoins des femmes présentant une DPC ; (b) évaluation clinique générale ; (c) évaluation pratique des niveaux de douleur ; (d) douleur myofasciale ; (e) médicaments et interventions chirurgicales ; (f) principes de la gestion des opiacés; (g) utilisation accrue de l'imagerie par résonance magnétique (IRM) ; (h) documentation de l'étendue de La maladie constatée au moyen de la chirurgie ; (i) thérapies non conventionnelles; (j) accès à des modèles de soins multidisciplinaires faisant appel à des composantes de physiothérapie (comme l'exercice et la posture) et de psychologie (comme La thérapie cognitivo- comportementale), conjointement avec d'autres disciplines médicales, telles que La gynécologie et l'anesthésie ; (k) attention accrue portée à La DPC dans La formation des professionnels de La sante ; et (l) attention accrue portée à la DPC dans le domaine des recherches officielles et de haut calibre. Le comité recommande que les ministères provinciaux de La Sante prennent des mesures en faveur de la création d'équipes multidisciplinaires pouvant assurer La prise en charge de cette pathologie. Chapitre 2 : Portee et definition de La douleur pelvienne chronique Chapitre 3 : Anamnese, examen physique et évaluation psychologique Chapitre 4 : Explorations Chapitre 5 : Sources de douleur pelvienne chronique Chapitre 6 : Causes urologiques et gastro-intestinales de La douleur pelvienne chronique Chapitre 7 : Dysfonctionnement myofasclal Chapitre 8 : Therapie medicale - résultats en matiere d'efficacite Chapitre 9 : Chirurgie - résultats en matiere d'efficacite Chapitre 11 : Prise en charge multidisciplinaire de La douleur chronique Chapitre 14 : Orientations futures.

Fezf2 promotes neuronal differentiation through localised activation of Wnt/ß-catenin signalling during forebrain development.

Brain regionalisation, neuronal subtype diversification and circuit connectivity are crucial events in the establishment of higher cognitive functions. Here we report the requirement for the transcriptional repressor Fezf2 for proper differentiation of neural progenitor cells during the development of the Xenopus forebrain. Depletion of Fezf2 induces apoptosis in postmitotic neural progenitors, with concomitant reduction in forebrain size and neuronal differentiation. Mechanistically, we found that Fezf2 stimulates neuronal differentiation by promoting Wnt/ß-catenin signalling in the developing forebrain. In addition, we show that Fezf2 promotes activation of Wnt/ß-catenin signalling by repressing the expression of two negative regulators of Wnt signalling, namely lhx2 and lhx9. Our findings suggest that Fezf2 plays an essential role in controlling when and where neuronal differentiation occurs within the developing forebrain and that it does so by promoting local Wnt/ß-catenin signalling via a double-repressor model.

A secretory cell type develops alongside multiciliated cells, ionocytes and goblet cells, and provides a protective, anti-infective function in the frog embryonic mucociliary epidermis.

The larval epidermis of Xenopus is a bilayered epithelium, which is an excellent model system for the study of the development and function of mucosal and mucociliary epithelia. Goblet cells develop in the outer layer while multiciliated cells and ionocytes sequentially intercalate from the inner to the outer layer. Here, we identify and characterise a fourth cell type, the small secretory cell (SSC). We show that the development of these cells is controlled by the transcription factor Foxa1 and that they intercalate into the outer layer of the epidermis relatively late, at the same time as embryonic hatching. Ultrastructural and molecular characterisation shows that these cells have an abundance of large apical secretory vesicles, which contain highly glycosylated material, positive for binding of the lectin, peanut agglutinin, and an antibody to the carbohydrate epitope, HNK-1. By specifically depleting SSCs, we show that these cells are crucial for protecting the embryo against bacterial infection. Mass spectrometry studies show that SSCs secrete a glycoprotein similar to Otogelin, which may form the structural component of a mucus-like protective layer, over the surface of the embryo, and several potential antimicrobial substances. Our study completes the characterisation of all the epidermal cell types in the early tadpole epidermis and reinforces the suitability of this system for the in vivo study of complex epithelia, including investigation of innate immune defences.

Brain tumour differentiation: rapid stratified serum diagnostics via attenuated total reflection Fourier-transform infrared spectroscopy.

The ability to diagnose cancer rapidly with high sensitivity and specificity is essential to exploit advances in new treatments to lead significant reductions in mortality and morbidity. Current cancer diagnostic tests observing tissue architecture and specific protein expression for specific cancers suffer from inter-observer variability, poor detection rates and occur when the patient is symptomatic. A new method for the detection of cancer using 1 µl of human serum, attenuated total reflection-Fourier transform infrared spectroscopy and pattern recognition algorithms is reported using a 433 patient dataset (3897 spectra). To the best of our knowledge, we present the largest study on serum mid-infrared spectroscopy for cancer research. We achieve optimum sensitivities and specificities using a Radial Basis Function Support Vector Machine of between 80.0 and 100 % for all strata and identify the major spectral features, hence biochemical components, responsible for the discrimination within each stratum. We assess feature fed-SVM analysis for our cancer versus non-cancer model and achieve 91.5 and 83.0 % sensitivity and specificity respectively. We demonstrate the use of infrared light to provide a spectral signature from human serum to detect, for the first time, cancer versus non-cancer, metastatic cancer versus organ confined, brain cancer severity and the organ of origin of metastatic disease from the same sample enabling stratified diagnostics depending upon the clinical question asked.

Inositol kinase and its product accelerate wound healing by modulating calcium levels, Rho GTPases, and F-actin assembly.

Wound healing is essential for survival. We took advantage of the Xenopus embryo, which exhibits remarkable capacities to repair wounds quickly and efficiently, to investigate the mechanisms responsible for wound healing. Previous work has shown that injury triggers a rapid calcium response, followed by the activation of Ras homolog (Rho) family guanosine triphosphatases (GTPases), which regulate the formation and contraction of an F-actin purse string around the wound margin. How these processes are coordinated following wounding remained unclear. Here we show that inositol-trisphosphate 3-kinase B (Itpkb) via its enzymatic product inositol 1,3,4,5-tetrakisphosphate (InsP4) plays an essential role during wound healing by modulating the activity of Rho family GTPases and F-actin ring assembly. Furthermore, we show that Itpkb and InsP4 modulate the speed of the calcium wave, which propagates from the site of injury into neighboring uninjured cells. Strikingly, both overexpression of itpkb and exogenous application of InsP4 accelerate the speed of wound closure, a finding that has potential implications in our quest to find treatments that improve wound healing in patients with acute or chronic wounds.

Growth hormone and cancer: GH production and action in glioma?

The hypersecretion of pituitary growth hormone (GH) is associated with an increased risk of cancer, while reducing pituitary GH signaling reduces this risk. Roles for pituitary GH in cancer are therefore well established. The expression of the GH gene is, however, not confined to the pituitary gland and it is now known to occur in many extrapituitary tissues, in which it has local autocrine or paracrine actions, rather than endocrine function. It is, for instance, expressed in cancers of the prostate, lung, skin, endometrium and colon. The oncogenicity of autocrine GH may also be greater than that induced by endocrine or exogenous GH, as higher concentrations of GHR antagonists are required to inhibit its actions. This may reflect the fact that autocrine GH is thought to act at intracellular receptors directly after synthesis, in compartments not readily accessible to endocrine (or exogenous) GH. The roles and actions of extrapituitary GH in cancer may therefore differ from those of pituitary GH. The possibility that GH may be expressed and act in glioma tumors was therefore examined by immunohistochemistry. These results demonstrate, for the first time, the presence of abundant GH- and GH receptor (GHR-) immunoreactivity in glioma, in which they were co-localized in cytoplasmic but not nuclear compartments. These results demonstrate that glioma differs from most cancers in lacking nuclear GHRs, but GH is nevertheless likely to have autocrine or paracrine actions in the induction and progression of glioma.

Effect of substrate choice and tissue type on tissue preparation for spectral histopathology by Raman microspectroscopy.

Raman spectroscopy is a non-destructive, non-invasive, rapid and economical technique which has the potential to be an excellent method for the diagnosis of cancer and understanding disease progression through retrospective studies of archived tissue samples. Historically, biobanks are generally comprised of formalin fixed paraffin preserved tissue and as a result these specimens are often used in spectroscopic research. Tissue in this state has to be dewaxed prior to Raman analysis to reduce paraffin contributions in the spectra. However, although the procedures are derived from histopathological clinical practice, the efficacy of the dewaxing procedures that are currently employed is questionable. Ineffective removal of paraffin results in corruption of the spectra and previous experiments have shown that the efficacy can depend on the dewaxing medium and processing time. The aim of this study was to investigate the influence of commonly used spectroscopic substrates (CaF2, Spectrosil quartz and low-E slides) and the influence of different histological tissue types (normal, cancerous and metastatic) on tissue preparation and to assess their use for spectral histopathology. Results show that CaF2 followed by Spectrosil contribute the least to the spectral background. However, both substrates retain paraffin after dewaxing. Low-E substrates, which exhibit the most intense spectral background, do not retain wax and resulting spectra are not affected by paraffin peaks. We also show a disparity in paraffin retention depending upon the histological identity of the tissue with abnormal tissue retaining more paraffin than normal.

Cn-AMP2 from green coconut water is an anionic anticancer peptide.

Globally, death due to cancers is likely to rise to over 20 million by 2030, which has created an urgent need for novel approaches to anticancer therapies such as the development of host defence peptides. Cn-AMP2 (TESYFVFSVGM), an anionic host defence peptide from green coconut water of the plant Cocos nucifera, showed anti-proliferative activity against the 1321N1 and U87MG human glioma cell lines with IC50 values of 1.25 and 1.85 mM, respectively. The membrane interactive form of the peptide was found to be an extended conformation, which primarily included ß-type structures (levels > 45%) and random coil architecture (levels > 45%). On the basis of these and other data, it is suggested that the short anionic N-terminal sequence (TES) of Cn-AMP2 interacts with positively charged moieties in the cancer cell membrane. Concomitantly, the long hydrophobic C-terminal sequence (YFVFSVGM) of the peptide penetrates the membrane core region, thereby driving the translocation of Cn-AMP2 across the cancer cell membrane to attack intracellular targets and induce anti-proliferative mechanisms. This work is the first to demonstrate that anionic host defence peptides have activity against human glioblastoma, which potentially provides an untapped source of lead compounds for development as novel agents in the treatment of these and other cancers.

FoxG1 and TLE2 act cooperatively to regulate ventral telencephalon formation.

FoxG1 is a conserved transcriptional repressor that plays a key role in the specification, proliferation and differentiation of the telencephalon, and is expressed from the earliest stages of telencephalic development through to the adult. How the interaction with co-factors might influence the multiplicity and diversity of FoxG1 function is not known. Here, we show that interaction of FoxG1 with TLE2, a Xenopus tropicalis co-repressor of the Groucho/TLE family, is crucial for regulating the early activity of FoxG1. We show that TLE2 is co-expressed with FoxG1 in the ventral telencephalon from the early neural plate stage and functionally cooperates with FoxG1 in an ectopic neurogenesis assay. FoxG1 has two potential TLE binding sites: an N-terminal eh1 motif and a C-terminal YWPMSPF motif. Although direct binding seems to be mediated by the N-terminal motif, both motifs appear important for functional synergism. In the neurogenesis assay, mutation of either motif abolishes functional cooperation of TLE2 with FoxG1, whereas in the forebrain deletion of both motifs renders FoxG1 unable to induce the ventral telencephalic marker Nkx2.1. Knocking down either FoxG1 or TLE2 disrupts the development of the ventral telencephalon, supporting the idea that endogenous TLE2 and FoxG1 work together to specify the ventral telencephalon.

Preliminary biological evaluation and mechanism of action studies of selected 2-arylindoles against glioblastoma.

A series of related 2-arylindoles have been evaluated for their anticancer activity against a range of glioblastoma cell lines using a number of different cell-based assays to determine cell viability after treatment with the compounds. The best indoles, which showed comparable activity to cisplatin against a U87MG cell line in the MTS assay, were taken forward and initial studies suggest that their mechanism of action is consistent with the generation of reactive oxygen species followed by autophagic cell death. Furthermore, activity was also observed in glioblastoma short-term cell cultures for the best lead compound and in some cases gave low micromolar IC50s.

Investigating the rapid diagnosis of gliomas from serum samples using infrared spectroscopy and cytokine and angiogenesis factors.

The ability to diagnose brain cancer rapidly from serum samples is of great interest; such a diagnosis would allow for rapid testing and time to results providing a responsive diagnostic environment, ability to monitor treatment efficacy, early detection of recurrent tumours and screening techniques. Current methods rely upon subjective, time-consuming tests such as histological grading and are particularly invasive with the diagnostic test requiring hospitalisation of 2-3 days. A rapid diagnostic method based upon serum samples would allow for a relatively non-invasive test and open up the possibility of screening for brain cancer. We report for the first time the use of a Bioplex immunoassay to provide cytokine and angiogenesis factor levels that differ between serum from glioma and non-cancer patients specifically angiopoietin, follistatin, HGF, IL-8, leptin, PDGF-BB and PECAM-1 providing sensitivities and specificities as high as 88 % and 81 %, respectively. We also report, for the first time, the use of serum ATR-FTIR combined with a RBF SVM for the diagnosis of gliomas from non-cancer patients with sensitivities and specificities as high as 87.5 % and 100 %, respectively. We describe the combination of these techniques in an orthogonal diagnostic regime, providing strength to the diagnosis through data combinations, in a rapid diagnostic test within 5 h from serum collection (10 min for ATR-FTIR and 4 h for the Bioplex Immunoassay). This regime has the ability to revolutionise the clinical environment by providing objective measures for diagnosis allowing for increased efficiency with corresponding decreases in mortality, morbidity and economic impact upon the health services.

Study of effectiveness of mifepristone for glioma cell line growth suppression.

OBJECTIVE: Glioblastoma multiforme is a malignant primary brain tumour with very limited treatment options. Any addition to existing treatment options which can improve prognosis and life expectancy is useful. In our study, we look at the usefulness of anti-progestogen mifepristone in causing growth suppression of glioma cell lines in the laboratory. METHODS: We cultured five cell lines in the lab and exposed them to mifepristone in different doses for a total of 96 h. Five different doses of mifepristone were used. Progesterone and dexamethasone were also used as growth stimulants. Immunostaining was used to identify progesterone receptors (PRs) in the cell lines. RESULTS: U257/7 and IN1265 showed statistically significant growth suppression (36% and 11%, P = 0.001 and 0.03 respectively), maximal at 96 h. Growth suppression in U257/7 showed a dose response progression except with the lowest dose which was not explicable. The response of IN1265 was seen only with the highest dose of mifepristone. There was no significant growth stimulation with either dexamethasone or progesterone. None of the cell lines showed any significant positivity for PRs. CONCLUSION: We were able to produce enough growth suppression of glioma cell lines using mifepristone. This is in keeping with some of the published results in literature. This raises the possibility of using mifepristone in treating GBMs which have very limited treatment options. This, however, needs further work probably on primary glioma cultures first followed by in vivo studies before it can be used in patients.

Genome-wide analysis of gene expression during Xenopus tropicalis tadpole tail regeneration.

BACKGROUND: The molecular mechanisms governing vertebrate appendage regeneration remain poorly understood. Uncovering these mechanisms may lead to novel therapies aimed at alleviating human disfigurement and visible loss of function following injury. Here, we explore tadpole tail regeneration in Xenopus tropicalis, a diploid frog with a sequenced genome. RESULTS: We found that, like the traditionally used Xenopus laevis, the Xenopus tropicalis tadpole has the capacity to regenerate its tail following amputation, including its spinal cord, muscle, and major blood vessels. We examined gene expression using the Xenopus tropicalis Affymetrix genome array during three phases of regeneration, uncovering more than 1,000 genes that are significantly modulated during tail regeneration. Target validation, using RT-qPCR followed by gene ontology (GO) analysis, revealed a dynamic regulation of genes involved in the inflammatory response, intracellular metabolism, and energy regulation. Meta-analyses of the array data and validation by RT-qPCR and in situ hybridization uncovered a subset of genes upregulated during the early and intermediate phases of regeneration that are involved in the generation of NADP/H, suggesting that these pathways may be important for proper tail regeneration. CONCLUSIONS: The Xenopus tropicalis tadpole is a powerful model to elucidate the genetic mechanisms of vertebrate appendage regeneration. We have produced a novel and substantial microarray data set examining gene expression during vertebrate appendage regeneration.