Now showing 1 - 10 of 621
  • Publication
    Current status of selected oral peptide technologies in advanced preclinical development and in clinical trials
    The development of oral dosage forms that allows absorption of therapeutic peptides to the systemic circulation is one of the greatest challenges for the pharmaceutical industry. Currently, a number of technologies including either mixtures of penetration enhancers or protease inhibitors and/or nanotechnology-based products are under clinical development. Typically, these formulations are presented in the form of enteric-coated tablets or capsules. Systems undergoing preclinical investigation include further advances in nanotechnology, including intestinal microneedle patches, as well as their combination with regional delivery to the colon. This review critically examines four selected promising oral peptide technologies at preclinical stage and the twelve that have progressed to clinical trials, as indicated in We examined these technologies under the criteria of peptide selection, formulation design, system components and excipients, intestinal mechanism of action, efficacy in man, and safety issues. The conclusion is that most of the technologies in clinical trials are incremental rather than paradigm-shifting and that even the more clinically-advanced oral peptide drugs examples of oral bioavailability appear to yield oral bioavailability values of only 1-2% and are, therefore, only currently suitable for a limited range of peptides.
      3707Scopus© Citations 232
  • Publication
    Whole-Organism Developmental Expression Profiling Identifies RAB-28 as a Novel Ciliary GTPase Associated with the BBSome and Intraflagellar Transport
    Primary cilia are specialised sensory and developmental signalling devices extending from the surface of most eukaryotic cells. Defects in these organelles cause inherited human disorders (ciliopathies) such as retinitis pigmentosa and Bardet-Biedl syndrome (BBS), frequently affecting many physiological and developmental processes across multiple organs. Cilium formation, maintenance and function depend on intracellular transport systems such as intraflagellar transport (IFT), which is driven by kinesin-2 and IFT-dynein motors and regulated by the Bardet-Biedl syndrome (BBS) cargo-adaptor protein complex, or BBSome. To identify new cilium-associated genes, we employed the nematode C. elegans, where ciliogenesis occurs within a short timespan during late embryogenesis when most sensory neurons differentiate. Using whole-organism RNA-Seq libraries, we discovered a signature expression profile highly enriched for transcripts of known ciliary proteins, including FAM-161 (FAM161A orthologue), CCDC-104 (CCDC104), and RPI-1 (RP1/RP1L1), which we confirm are cilium-localised in worms. From a list of 185 candidate ciliary genes, we uncover orthologues of human MAP9, YAP, CCDC149, and RAB28 as conserved cilium-associated components. Further analyses of C. elegans RAB-28, recently associated with autosomal-recessive cone-rod dystrophy, reveal that this small GTPase is exclusively expressed in ciliated neurons where it dynamically associates with IFT trains. Whereas inactive GDP-bound RAB-28 displays no IFT movement and diffuse localisation, GTP-bound (activated) RAB-28 concentrates at the periciliary membrane in a BBSome-dependent manner and undergoes bidirectional IFT. Functional analyses reveal that whilst cilium structure, sensory function and IFT are seemingly normal in a rab-28 null allele, overexpression of predicted GDP or GTP locked variants of RAB-28 perturbs cilium and sensory pore morphogenesis and function. Collectively, our findings present a new approach for identifying ciliary proteins, and unveil RAB28, a GTPase most closely related to the BBS protein RABL4/IFT27, as an IFT-associated cargo with BBSome-dependent cell autonomous and non-autonomous functions at the ciliary base.
      655Scopus© Citations 42
  • Publication
    The symptom phenotype of oncology outpatients remains relatively stable from prior to through one week following chemotherapy
    Some oncology outpatients experience a higher number of and more severe symptoms during chemotherapy (CTX). However, little is known about whether this high risk phenotype persists over time. Latent transition analysis (LTA) was used to examine the probability that patients remained in the same symptom class when assessed prior to the administration of and following their next dose of CTX. For the patients whose class membership remained consistent, differences in demographic and clinical characteristics, and quality of life (QOL) were evaluated. The Memorial Symptom Assessment Scale (MSAS) was used to evaluate symptom burden. LTA was used to identify subgroups of patients with distinct symptom experiences based on the occurrence of the MSAS symptoms. Of the 906 patients evaluated, 83.9% were classified in the same symptom occurrence class at both assessments. Of these 760 patients, 25.0% were classified as Low-Low, 44.1% as Moderate-Moderate and 30.9% as High-High. Compared to the Low-Low class, the other two classes were younger, more likely to be women and to report child care responsibilities, and had a lower functional status and a higher comorbidity scores. The two higher classes reported lower QOL scores. The use of LTA could assist clinicians to identify higher risk patients and initiate more aggressive interventions.
      250Scopus© Citations 33
  • Publication
    Control of mycobacterium bovis infection in two sika deer herds in Ireland
    (Springer (Biomed Central Ltd.), 2008) ; ; ;
    In a number of countries, tuberculosis (due to infection with Mycobacterium bovis) is a significant health problem of captive deer. This paper describes outbreaks of bovine tuberculosis in sika deer (Cervus nippon) on two farms in Ireland and the methods used to control the disease. On Farm A, infection was first detected during 1993. The infection was eradicated using a programme of test and removal, in association with segregation of young animals. A second outbreak (also due to infection with M. bovis, but a different RFLP profile) was detected in 2002. In the latter outbreak, infection was particularly prevalent in two groups of young deer. M. bovis with the same RFLP profile was also isolated in a badger found dead on the farm. Control was achieved by test and removal in association with herd management changes. In Herd B, infection was first detected in 1995, and subsequently eradicated using test and removal alone. In Herd A, re-infection remains an ongoing risk. Control rather than eradication of infection may more realistic in the short-to medium-term.
      330Scopus© Citations 7
  • Publication
    Exposure of bovine oocytes and embryos to elevated non-esterified fatty acid concentrations: integration of epigenetic and transcriptomic signatures in resultant blastocysts
    Background: Metabolic stress associated with negative energy balance in high producing dairy cattle and obesity in women is a risk factor for decreased fertility. Non-esterified fatty acids (NEFA) are involved in this pathogenesis as they jeopardize oocyte and embryo development. Growing evidence indicates that maternal metabolic disorders can disturb epigenetic programming, such as DNA methylation, in the offspring. Oocyte maturation and early embryo development coincide with methylation changes and both are sensitive to adverse environments. Therefore, we investigated whether elevated NEFA concentrations affect establishment and maintenance of DNA methylation in oocytes and embryos, subsequently altering transcriptomic profiles and developmental competence of resultant blastocysts. Results: Bovine oocytes and embryos were exposed to different NEFA concentrations in separate experiments. In the first experiment, oocytes were matured in vitro for 24 h in medium containing: 1) physiological ('BASAL') concentrations of oleic (OA), palmitic (PA) and stearic (SA) acid or 2) pathophysiological ('HIGH COMBI') concentrations of OA, PA and SA. In the second experiment, zygotes were cultivated in vitro for 6.5 days under BASAL or HIGH COMBI conditions. Developmental competence was evaluated by assessing cleavage and blastocyst rate. Overall gene expression and DNA methylation of resultant blastocysts were analyzed using microarray. DNA methylation data were re-evaluated by pyrosequencing. HIGH COMBI-exposed oocytes and embryos displayed a lower competence to develop into blastocysts compared to BASAL-exposed counterparts (19.3% compared to 23.2% and 18.2% compared to 25.3%, respectively) (P < 0.05). HIGH COMBI-exposed oocytes and embryos resulted in blastocysts with altered DNA methylation and transcriptomic fingerprints, compared to BASAL-exposed counterparts. Differences in gene expression and methylation were more pronounced after exposure during culture compared to maturation suggesting that zygotes are more susceptible to adverse environments. Main gene networks affected were related to lipid and carbohydrate metabolism, cell death, immune response and metabolic disorders. Conclusions: Overall, high variation in methylation between blastocysts made it difficult to draw conclusions concerning methylation of individual genes, although a clear overview of affected pathways was obtained. This may offer clues regarding the high rate of embryonic loss and metabolic diseases during later life observed in offspring from mothers displaying lipolytic disorders.
      291Scopus© Citations 69
  • Publication
    Coseismic velocity variations caused by static stress changes associated with the 2001 Mw=4.3 Agios Ionis earthquake in the Gulf of Corinth, Greece
    (American Geophysical Union, 2010-07) ; ; ;
    The analysis of temporal variations in the seismic velocity across faults can be used to estimate in situ stress changes. Seismic velocity of propagation depends on the fault stiffness, which is a function of stress. The coda wave interferometry technique is applied to seven families of repeating earthquakes (multiplets) recorded on the southern shore of the Gulf of Corinth, Greece, to estimate high precision velocity changes in the Earth ’ s crust associated with the M w = 4.3 Agios Ioanis earthquake. Results show that the Agios Ioanis event causes a perturbation in elastic properties at seismogenic depth, resulting in a reduction of 0.2% in the seismic velocity. The results are not consistent with either damage induced by dynamic stresses nor a fluid transient origin. In contrast, both the spatial distribution and magnitude of the velocity perturbation correlate well with modeled static stress variations. This suggests that the measured changes in the mechanical properties of the seismogenic crust can be attributed to a change in static stress field associated with the M w = 4.3 Agios Ioanis earthquake. The velocity changes indicate an unclamping of the Pyrgaki fault at depth, which has local hazard implications
  • Publication
    SParTSim: A Space Partitioning Guided by Road Network for Distributed Traffic Simulations
    Traffic simulation can be very computationally intensive, especially for microscopic simulations of large urban areas (tens of thousands of road segments, hundreds of thousands of agents) and when real-time or better than real-time simulation is required. For instance, running a couple of what-if scenarios for road management authorities/police during a road incident: time is a hard constraint and the size of the simulation is relatively high. Hence the need for distributed simulations and for optimal space partitioning algorithms, ensuring an even distribution of the load and minimal communication between computing nodes. In this paper we describe a distributed version of SUMO, a simulator of urban mobility, and SParTSim, a space partitioning algorithm guided by road network for distributed simulations. It outperforms classical uniform space partitioning in terms of road segment cuts and load-balancing.
      1271Scopus© Citations 21
  • Publication
    The analysis of serum response factor expression in bone and soft tissue prostate cancer metastases
    Castration-resistant prostate cancer (CRPC) represents a challenge to treat with no effective treatment options available. We recently identified serum response factor (SRF) as a key transcription factor in an in vitro model of castration resistance where we showed that SRF inhibition resulted in reduced cellular proliferation. We also demonstrated an association between SRF protein expression and CRPC in a cohort of castrate-resistant transurethral resections of the prostate (TURPS). The mechanisms regulating the growth of CRPC bone and visceral metastases have not been explored in depth due to the paucity of patient-related material available for analysis. In this study, we aim to evaluate SRF protein expression in prostate cancer (PCa) metastases, which has not previously been reported.
      503Scopus© Citations 15
  • Publication
    Hierarchical Modularity and the Evolution of Genetic Interactomes across Species
    To date, cross-species comparisons of genetic interactomes have been restricted to small or functionally related gene sets, limiting our ability to infer evolutionary trends. To facilitate a more comprehensive analysis, we constructed a genome-scale epistasis map (E-MAP) for the fission yeast Schizosaccharomyces pombe, providing phenotypic signatures for ~60% of the nonessential genome. Using these signatures, we generated a catalog of 297 functional modules, and we assigned function to 144 previously uncharacterized genes, including mRNA splicing and DNA damage checkpoint factors. Comparison with an integrated genetic interactome from the budding yeast Saccharomyces cerevisiae revealed a hierarchical model for the evolution of genetic interactions, with conservation highest within protein complexes, lower within biological processes, and lowest between distinct biological processes. Despite the large evolutionary distance and extensive rewiring of individual interactions, both networks retain conserved features and display similar levels of functional crosstalk between biological processes, suggesting general design principles of genetic interactomes.
      611Scopus© Citations 149
  • Publication
    Phosphodiesterase-8A binds to and regulates Raf-1 kinase
    (Proceedings of the National Academy of Sciences, 2013-03-18) ; ; ;
    V-raf-1 murine leukemia viral oncogene homolog 1 (Raf-1) is a key activator of the ERK pathway and is a target for cross-regulation of this pathway by the cAMP signaling system. The cAMP-activated protein kinase, PKA, inhibits Raf-1 by phosphorylation on S259. Here, we show that the cAMP-degrading phosphodiesterase-8A (PDE8A) associates with Raf-1 to protect it from inhibitory phosphorylation by PKA, thereby enhancing Raf-1’s ability to stimulate ERK signaling. PDE8A binds to Raf-1 with high (picomolar) affinity. Mapping of the interaction domain on PDE8A using peptide array technology identified amino acids 454–465 as the main binding site, which could be disrupted by mutation. A cell-permeable peptide corresponding to this region disrupted the PDE8A/Raf-1 interaction in cells, thereby reducing ERK activation and the cellular response to EGF. Overexpression of a catalytically inactive PDE8A in cells displayed a dominant negative phenotype on ERK activation. These effects were recapitulated at the organism level in genetically modified (PDE8A−/−) mice. Similarly, PDE8 deletion in Drosophila melanogaster reduced basal ERK activation and sensitized flies to stress-induced death. We propose that PDE8A is a physiological regulator of Raf-1 signaling in some cells.
      442Scopus© Citations 43