• Cannabinoid receptor systems: therapeutic targets for tumour intervention.

      Jones, Sarah; Howl, John D. (Taylor & Francis (Informa Healthcare), 2003)
      The past decade has witnessed a rapid expansion of our understanding of the biological roles of cannabinoids and their cognate receptors. It is now certain that Delta9-tetrahydrocannabinol, the principle psychoactive component of the Cannabis sativa plant, binds and activates membrane receptors of the 7-transmembrane domain, G-protein-coupled superfamily. Several putative endocannabinoids have since been identified, including anandamide, 2-arachidonyl glycerol and noladin ether. Synthesis of numerous cannabinomimetics has also greatly expanded the repertoire of cannabinoid receptor ligands with the pharmacodynamic properties of agonists, antagonists and inverse agonists. Collectively, these ligands have proven to be powerful tools both for the molecular characterisation of cannabinoid receptors and the delineation of their intrinsic signalling pathways. Much of our understanding of the signalling mechanisms activated by cannabinoids is derived from studies of receptors expressed by tumour cells; hence, this review provides a succinct summary of the molecular pharmacology of cannabinoid receptors and their roles in tumour cell biology. Moreover, there is now a genuine expectation that the manipulation of cannabinoid receptor systems may have therapeutic potential for a diverse range of human diseases. Thus, this review also summarises the demonstrated antitumour actions of cannabinoids and indicates possible avenues for the future development of cannabinoids as antitumour agents.
    • Case study of Felty’s Syndrome

      Nelson, Paul N.; Bowman, S.J. (Oxford: Blackwell Publishing, 2001)
      This book: is an introductory level text on the biological principles of human disease. The book is aimed at medical students in degree courses in biomedical science. The book fuses the biological (physiological and biochemical) processes which underlie the clinical manifestations of disease. As such, it brings together material which is conventionally dealt with by several books. The authors have covered the fundamentals of each topic in a readable manner, which should encourage students to develop a fuller understanding, where necessary, by reference to more comprehensive texts.
    • CEL1: a novel cellulose binding protein secreted by Agaricus bisporus during growth on crystalline cellulose.

      Armesilla, Angel Luis; Thurston, Christopher F.; Yague, Ernesto (Blackwell Publishing, 1994)
      The cel1 gene of Agaricus bisporus encodes a protein (CEL1) that has an architecture resembling the multi-domain fungal cellulases, although the sequence of its putative catalytic core is not matched by any other in the protein and nucleic acid data bases. The N-terminal half of the putative catalytic domain of CEL1 was expressed in Escherichia coli as a fusion protein with glutathione-S-transferase. The fusion protein was used to raise a CEL1-specific antibody. CEL1 was detected as an extracellular 49.8 kDa protein in A. bisporus cellulose-grown cultures, where it bound strongly to cellulose. CEL1 was neither an endoglucanase, a cellobiohydrolase able to hydrolyze fluorogenic cellobiosides, a beta-glucosidase, a xylanase, nor a cellobiose: quinone oxidoreductase. CEL1 was present in some fractions of culture fluid separated by electrophoresis which released soluble sugars from crystalline cellulose.
    • Cell penetrating peptides as signal transduction modulators

      Jones, Sarah; Howl, John D. (CRC Press (Taylor & Francis), 2007)
      THIS BOOK: Since the first Handbook of Cell-Penetrating Peptides was prepared in 2001, the wealth of new information on the use of these peptides as transport systems has in fact served to confound the field. The constant internal change in the field of cell-penetrating peptides (CPPs) is due to recent research uncovering apparent ambiguities in cellular uptake. There is still neither a common terminology nor a uniform explanation for the penetrative mechanism of cell-penetrating peptides. In this second edition of the Handbook of Cell-Penetrating Peptides, the authors summarize the current state of the field including recent reevaluations of earlier studies of CPP mechanisms. Beginning with an overview of the classes of peptides and their individual uptake mechanisms, from the earlier lipid models to the more recent endocytotic pathways, the book demonstrates the diversity and the opportunity for these biologically active proteins to serve as future drug leads. The text then covers the use of CPPs in gene modulation, addressing the application of antisense and decoy oligonucleotides, as well as the new avenue of research targeting specific tumors and other tissues-questions that had barely been asked when the first edition was published. By summarizing the diffuse information regarding CPPs, including the ambiguities and variety of mechanisms, the Handbook of Cell-Penetrating Peptides provides the most solid foundation available from which to expand the potential of this rapidly growing field of medicine. (CRC Press)
    • Cell-Penetrating Peptides

      Howl, John; Jones, Sarah (2015)
      The multi-domain architecture of many human proteins provides a structural basis for the physical maintenance of interactomes, or networks of protein-protein interactions (PPIs), that are so obviously crucial to cellular functions. Moreover, the structural and electrostatic complementarity provided by PPI interfaces, predominantly located on protein surfaces, is a fundamental component of signal transduction events that are known to be compromised in human diseases including many cancers.The pharmacokinetic advantages provided by cell-penetrating peptides (CPPs) are entirely compatible with the development of intrinsically permeable agents capable of modulating intracellular PPIs. Thus, the term bioportide is a useful descriptor of numerous bioactive CPPs that are distinct from the more usual inert CPP vectors. Herein we illustrate a generic strategy, predominantly centered upon the identification of cationic peptides derived from helical protein domains, which offers a reliable platform to identify bioportides capable of modulating intracellular signal transduction events. In addition, we describe robust methodologies to determine the precise intracellular distribution of fluorescent bioportides and present assays routinely employed to screen for the detrimental pharmacodynamic properties often exhibited by both CPPs and bioportides; namely adverse cytotoxicity and the receptor-independent stimulation of mast cell secretion.
    • Cellular pathology of atherosclerosis: smooth muscle cells promote adhesion of platelets to cocultured endothelial cells.

      Tull, Samantha P.; Anderson, Stephen I.; Hughan, Sascha C.; Watson, Steve P.; Nash, Gerard B.; Rainger, G.E. (American Heart Association, Inc., 2006)
      Although platelets do not ordinarily bind to endothelial cells (EC), pathological interactions between platelets and arterial EC may contribute to the propagation of atheroma. Previously, in an in vitro model of atherogenesis, where leukocyte adhesion to EC cocultured with smooth muscle cells was greatly enhanced, we also observed attachment of platelets to the EC layer. Developing this system to specifically model platelet adhesion, we show that EC cocultured with smooth muscle cells can bind platelets in a process that is dependent on EC activation by tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1. Recapitulating the model using EC alone, we found that a combination of TGF-beta1 and TNF-alpha promoted high levels of platelet adhesion compared with either agent used in isolation. Platelet adhesion was inhibited by antibodies against GPIb-IX-V or alpha(IIb)beta3 integrin, indicating that both receptors are required for stable adhesion. Platelet activation during interaction with the EC was also essential, as treatment with prostacyclin or theophylline abolished stable adhesion. Confocal microscopy of the surface of EC activated with TNF-alpha and TGF-beta1 revealed an extensive matrix of von Willebrand factor that was able to support the adhesion of flowing platelets at wall shear rates below 400 s(-1). Thus, we have demonstrated a novel route of EC activation which is relevant to the atherosclerotic microenvironment. EC activated in this manner would therefore be capable of recruiting platelets in the low-shear environments that commonly exist at points of atheroma formation.
    • Changes in growth and gene expression induced by sulphur deficiency in garlic

      Wei, Wenxue; Bilsborrow, Paul E.; Hooley, Paul; Bibi, H. (Taylor & Francis, 2002)
      Sulfur deficiency in garlic Allium sativum L. caused a reduction in growth together with chlorosis and necrosis of leaves. Large differences in shoot sulfur and sulphate concentrations between deficient and high sulfur treatments were only observed after 54 days growth. Using the mRNA differential display technique, a novel cDNA was isolated from shoots grown in sulfur depleted nutrient solution for 24 days. This novel cDNA was constitutively expressed in the shoots during further growth in sulfur depleted solution, but it was undetectable following 30 days recovery with sulfur supplementation. The cDNA sequence demonstrated a high degree of identity with a coat protein gene of a garlic latent carlavirus. The results suggest a possible relationship between low plant sulfur status and the induction of a latent carlavirus in garlic.
    • Characterisation and in vitro antimicrobial potential of liposome encapsulated silver ions against Candida albicans.

      Kenward, M A; Hill, D J; Martin, C; Low, Wan Li (Taylor & Francis, 2016-01-20)
      Liposomes are biocompatible, biodegradable, controlled delivery systems with the ability to encapsulate both lipophilic and hydrophilic compounds, including metal ions. Liposome encapsulated Ag(+) (lipo-Ag(+)), prepared by reverse-phase evaporation, was used as a controlled delivery system against Candida albicans. Characterisation of the lipo-Ag(+) indicated that the multilamellar vesicles with diameters ranging between ≈ 0.5 and 5.0 μm showed potential as a controlled delivery system to consistently deliver Ag(+) to C. albicans. Results from inductively coupled plasma (ICP) analysis showed higher association of cell bound Ag(+) at 15 mins post exposure when compared to unencapsulated Ag(+). Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) indicate detrimental effects of Ag(+) on C. albicans cell structure. These effects along with the ICP results also correlate with previously reported time kill experiment observations.
    • Characterisation of epitopes of pan-IgG/anti-G3m(u) and anti-Fc monoclonal antibodies.

      Nelson, Paul N.; Westwood, Olwyn M. R.; Soltys, Andy; Jefferis, Roy; Goodall, Margaret; Baumforth, Karl R. N.; Frampton, Geoffrey; Tribbick, Gordon; Roden, Denise A.; Hay, Frank C. (Elsevier BV, 2003)
      The characterisation of monoclonal antibodies (MAbs) and their epitopes is important prior to their application as molecular probes. In this study, Western blotting using IgG1 Fc and pFc' fragments was employed to screen seven MAbs before pepscan analysis to determine their reactivity to potentially linear epitopes. MAbs PNF69C, PNF110A, X1A11 and MAbs WC2, G7C, JD312, 1A1 detected epitopes within the C(H)3 and C(H)2 domains, respectively. However, only four MAbs showed pepscan profiles that highlighted likely target residues. In particular, MAbs PNF69C and PNF110A that have previously been characterised with pan-IgG and anti-G3m(u) specificity, detected the peptide motif 338-KAKGQPR-344 which was located within the N-terminal region of the C(H)3 domain. Furthermore the majority of residues were present in all four IgG subclasses. Consequently the peptide identified was consistent with the pan-IgG nature of these antibodies. By using PCImdad, a molecular display programme, this sequence was visualised as surface accessible, located in the C(H)2/C(H)3 inter-domain region and proximal to the residue arginine(435). It is speculated that this residue may be important for phenotypic expression of G3m(u) and specificity of these reagents. Pepscan analysis of MAbs G7C and JD312 (both pan-IgG) highlighted the core peptide sequence 290-KPREE-294, which was present in the C(H)2 domain and was common to all four IgG subclasses. PCImdad also showed this region to be highly accessible and was consistent with previous bioinformatic and autoimmune analysis of IgG. Overall these MAbs may serve as useful anti-IgG or anti-G3m(u) reagents and probes of immunoglobulin structure.
    • Characterization of anti-myosin monoclonal antibodies.

      Nelson, Paul N.; Astley, S.J.; Roden, Denise A.; Waldron, E.E.; Baig, K.M.; Caforio, A.L.; Koutedakis, Yiannis; Perera, Shantha; Spry, C. (New Rochelle (NY): Mary Ann Liebert, Inc., 2005)
      The characterization of monoclonal antibodies (MAbs) with regard to reactivity and specificity is important for the successful application as a molecular probe and/or diagnostic reagent. Furthermore, it is recognized that some monoclonal reagents perform well in some assay systems but not others. In this study, the reactivity profiles of two anti-myosin MAbs (H1 and DH2, raised against human cardiac myosin) were evaluated in enzyme-linked immunosorbent assay (ELISA), slot-blotting, and immunocytochemistry. Both antibodies performed well in slot-blotting against myosin heavy chain preparations from cardiac and skeletal muscle and from non-human sources. In general, MAb H1 demonstrated strong to moderate reactivity in all assay systems, whilst MAb DH2 faired poorly in ELISA. MAb H1 also showed reactivity to synthetic peptides of myosin, one of which possessed a motif (ERRDA, single amino acid code) that was found in other human and nonhuman myosin protein sequences that could explain its cross-reactive profile. Intriguingly, this motif was found on viral and other pathogenic agents associated with myocarditis. Hence, it is speculated that this region could give some credence to the mechanism of molecular mimicry associated with some cardiac diseases. Overall, MAb H1 may serve as a useful probe of myosin structure.
    • Charge delocalisation and the design of novel mastoparan analogues: enhanced cytotoxicity and secretory efficacy of [Lys5, Lys8, Aib10]MP.

      Jones, Sarah; Howl, John D. (Elsevier BV, 2004)
      The formation of an amphipathic helix is a major determinant of the biological activity of the tetradecapeptide mastoparan (MP). To address the functional significance of lysyl residues at positions 4, 11 and 12 of MP, we synthesised five novel analogues using sequence permutation and arginine-substitution to delocalise cationic charge. Comparative bioassays determined cytotoxicity, beta-hexoseaminidase secretory efficacy and peptide-activated extracellular receptor-stimulated kinase (ERK)1/2 phosphorylation. The monosubstitution of individual lysine residues with arginine produced differential changes to the indices of cytotoxicity and secretion indicating that these conservative substitutions are compatible with membrane translocation and the selective binding and activation of intracellular proteins. More profound changes to the predicted hydrophilic face of MP, resulting from the relocation or substitution of additional lysyl residues, enhanced both the cytotoxicity and secretory efficacy of novel peptides. Significantly, the more amphipathic peptide [Lys5, Lys8, Aib10]MP was identified to be both the most cytotoxic and the most potent secretagogue of all the peptides compared here. Charge delocalisation within the hydrophilic face of MP analogues was also compatible with peptide-induced activation of ERK1/2 phosphorylation. Our data indicate that charge delocalisation is a suitable strategy to engineer more potent analogues of MP that differentially target intracellular proteins.
    • Chimeric peptides as tumour-selective delivery systems.

      Jones, Sarah; Howl, John D. (Society for Neuro-oncology and Duke University Press, 2005)
      The cell-type-specific targeting of cytotoxic agents and other functional moieties can be achieved by using peptidyl address motifs that selectively bind protein targets expressed at high density at the cell membrane. Indeed, numerous studies have confirmed the utility of ligands for G protein–coupled receptors as components of heterofunctional peptide chimeras that are selective biological probes. Our current efforts are directed toward the further development of chimeric peptidyl constructs that employ sequences derived from GPCR ligands or cell penetrant motifs to affect the selective delivery of cytotoxins and signal transduction modulators to tumor cells. We have designed and synthesized a range of hybrid constructs consisting of cytotoxins (peptide and non-peptide) covalently linked to an address peptide derived from the C-terminal of gastrin (G7; H-AYGWMDF-NH2). The G7 homing motif targets a novel binding site expressed by U373MG astrocytic tumor cells that is distinct from classical CCK1/CCK2 receptors. Moreover, biological responses following activation of this novel membrane-bound protein may offer additional therapeutic advantages. For example, G7 receptor activation is reported to inhibit the motility of malignant astrocytoma in vivo while avoiding the growth-promoting effects of gastrin (Pannequin et al., J. Pharmacol. Exp. Ther. 302, 274, 2002). We evaluated the cytotoxicity of our chimeric peptides by comparing changes in cellular viability using MTT conversion assays. Our data indicate that chimeric peptides dose-dependently and rapidly (<8 h) reduced the viability of U373MG cells. Moreover, as a chimeric amino-terminal extension, the G7 address motif enhanced the cytotoxicity of both mastoparan (H-INLKALAALAKKIL-NH2) and D(KLAKLAK)2 peptides reported to stimulate necrosis and/or apoptosis of eukarytoic cells. In conclusion, hybrid G7 chimeras enhance the efficacy of cytotoxic agents and may be valuable probes to investigate and manipulate additional aspects of astrocytoma cell biology. This work was supported by The Wellcome Trust.
    • Cholesterol-bile salt vesicles as potential delivery vehicles for drug and vaccine delivery.

      Martin, C.; Thongborisute, J.; Takeuchi, H.; Yamamoto, H.; Kawashima, Y.; Alpar, H.O. (Elsevier Science Direct, 2005)
      The aim of this study was to further investigate the interactions between cholesterol (CH) and mixed bile salts (BS) (sodium cholate and sodium deoxycholate) and their suitability for drug and vaccine delivery. Insulin was used as a model protein to assess the ability of CH:BS vesicles to entrap a therapeutically relevant macromolecule. The association of protein (FITC-insulin) with the CH:BS structure was confirmed with fluorescence microscopy, and the overall morphology of the vesicles was examined with atomic force microscopy (AFM). Results demonstrate that the nature of the vesicles formed between CH and BS is dependent not only on the concentration of BS but also on the increasing CH concentration leading to CH crystal formation.
    • Cloning of a novel gene encoding a C2H2 zinc finger protein that alleviates sensitivity to abiotic stresses in Aspergillus nidulans

      O'Neil, John D.; Bugno, Marcin; Stanley, Michele S.; Barham-Morris, Julia B.; Woodcock, Nicola A.; Clement, Darren J.; Clipson, Nicholas J. W.; Whitehead, Michael P.; Fincham, Daron A.; Hooley, Paul (Elsevier Science Direct, 2002)
      We report the cloning and sequencing of a DNA fragment encoding a putative C2H2 zinc finger protein from Aspergillus nidulans. The gene was isolated by complementation cloning of a salt sensitive phenotype of the A. nidulans sltAl mutant. A 3.8 kb Pst I fragment that restored wild type salt tolerance contained one large open reading frame of 2202 bp. The predicted protein (StzA) from this reading frame comprises 698 amino acids and has three Zinc fingers along with a putative transcriptional activation domain rich in acidic amino acids. The corresponding sequence from a sltAl mutant contains a premature STOP codon resulting in loss of the putative transcriptional activator in the C-terminal region. The Zinc fingers show conserved motifs with a number of transcription factors including CreA from A. nidulans and the human Wilm's tumour susceptibility protein WT-1.
    • Combination of inhibitors of lymphocyte activation (hydroxyurea, trimidox, and didox) and reverse transcriptase (didanosine) suppresses development of murine retrovirus-induced lymphoproliferative disease.

      Mayhew, Christopher N.; Sumpter, Ryan; Inayat, Mohammed; Cibull, Michael; Phillips, Jonathan D.; Elford, Howard L.; Gallicchio, Vincent S. (Elsevier Science Direct, 2005)
      The ribonucleotide reductase inhibitor hydroxyurea (HU) has demonstrated some benefit as a component of drug cocktails for the treatment of HIV-1 infection. However, HU is notoriously myelosuppressive and often administered only as salvage therapy to patients with late-stage disease, potentially exacerbating the bone marrow toxicity of HU. In this report we have compared the antiviral effects of HU and two novel RR inhibitors trimidox (3,4,5-trihydroxybenzamidoxime) and didox (3,4-dihydroxybenzohydroxamic acid) in combination with didanosine (2,3-didoxyinosine; ddI) in the LPBM5 MuLV retrovirus model (murine AIDS). We also evaluated the effects of these drug combinations on the hematopoietic tissues of LPBM5 MuLV-infected animals. The combination of RR inhibitors and ddI was extremely effective (DX>TX>HU) in inhibiting development of retrovirus-induced disease (splenomegaly, hypergammaglobulinemia, activated B-splenocytes and loss of splenic architecture). In addition, relative levels of proviral DNA were significantly lower in combination drug-treated animals compared to infected controls. Evaluation of femur cellularity, numbers of marrow-derived myeloid progenitor cells (CFU-GM and BFU-E) and peripheral blood indices revealed that TX and DX in combination with ddI were well-tolerated. However, treatment with HU and ddI induced moderate myelosuppression. These data demonstrate that RR inhibitors in combination with ddI provide significant protection against retroviral disease in murine AIDS. Moreover, the novel RR inhibitors TX and DX appear to be more effective and less myelosuppressive than HU when administered with ddI in this model.
    • Comparative evaluation of drug release from aged prolonged polyethylene oxide tablet matrices: effect of excipient and drug type.

      Shojaee, Saeed; Kaialy, Waseem; Cumming, Kenneth Iain; Nokhodchi, Ali (Informa healthcare, 2014-11-20)
      Abstract Polyethylene oxide (PEO) undergoes structural adjustments caused by elevated temperatures, which results in loss of its stability within direct compression tablets. The aim of this study was to evaluate the influence of filler solubility on the drug delivery process of matrix tablets containing drugs with different water-solubility properties and stored at elevated temperature. The results demonstrated that in the case of propranolol HCl (highly water-soluble) tablet matrices, soluble lactose promoted drug release, whereas, a stable release of drug was observed with insoluble DCP. A drug release pattern similar to the propranolol HCl formulation containing DCP was obtained for hydrophilic matrix tablets containing either lactose or DCP for the less water-soluble drug, zonisamide. In the case of the partially water-soluble drug, theophylline, formulated with lower molecular weight PEO 750, drug release increased considerably in the presence of both fillers with increasing storage time, however a stable release rate (similar to fresh samples) was observed in the case of higher molecular weight PEO 303 tablet matrices containing theophylline with either lactose or DCP. The hydration properties (e.g. solubility) of the diluents had a considerable effect on drug release behavior from various model matrices; this effect was dependent on both molecular weight of PEO and solubility of drug.
    • Comparison of Antigenic Regions Identified on IgG1Fc Using Bioinformatics vs Pepscan Analysis

      Nelson, Paul N.; Westwood, Olwyn M. R.; Freimanis, Graham L.; Roden, Denise A.; Sissaoui, Samir; Rylance, Paul; Hay, Frank C. (Libertas Academica Press, 2008)
      Epitope mapping allowed the location of antigenic determinants on a protein macromolecule to be identified. In particular, pepscan techniques that utilize a series of overlapping peptides, help detect key amino acid residues that are important in antibody recognition and binding. In a previous study, we employed 15-mer peptides spanning the entire length of IgG1Fc to ascertain successfully the target epitopes of isotypic/allotypic monoclonal reagents. As an extension to this work we have used these peptides to evaluate the location of epitope targets of five IgM rheumatoid factor antibodies (RFAbs). Overall, 2 antibodies, RFAb TS2 and TS1, detected a similar epitope within the CH3 domain (360-KNQVSLTCLVKGFYP-374), whilst 1 (RFAb SJ1) recognised an epitope in the CH2 domain (294- EQYNSTYRVVSVLTV-308). In contrast, 2 RFAbs, PRSJ2 and PRTS1 detected four and five epitopes respectively within the Fc region. RFAb PRSJ2 recognised epitopes detected by RFAB TS2 and TS1 but also further epitopes in the CH2 domain (256-TPEVTCVVVDVSHED-270) and CH3 domain (418-QQGNVFSCSVMHEAL-432). Similarly, RFAb PRTS1 detected all four epitopes plus a fifth in the CH3 domain (382-ESNGQPENNYKTTPP-396). In essence there was a consensus of target epitopes identified by these rheumatoid factor antibodies. Interestingly, two epitopes (256–270, CH2 domain and 360–374, CH3 domain) were novel in that they had not been identified in previous pepscan studies. The other epitopes recognised, either overlapped or were immediately adjacent to previous epitopes detected by poly/monoclonal rheumatoid factor antibodies. Molecular modelling (PCImdad) of IgG1Fc showed that all five epitopes were exposed and surface accessible for antibody interaction. In addition, a bioinformatics analysis of the Fc region using ExPASy was employed to identify key antigenic determinants. This ‘in silico’ approach may provide a means of determining key regions without the need to develop overlapping peptides spanning the entire length of a macromolecule.
    • Computational predictions of glass-forming ability and crystallization tendency of drug molecules.

      Alhalaweh, Amjad; Alzghoul, Ahmad; Kaialy, Waseem; Mahlin, Denny; Bergström, Christel A S (ACS Publications, 2014-09-02)
      Amorphization is an attractive formulation technique for drugs suffering from poor aqueous solubility as a result of their high lattice energy. Computational models that can predict the material properties associated with amorphization, such as glass-forming ability (GFA) and crystallization behavior in the dry state, would be a time-saving, cost-effective, and material-sparing approach compared to traditional experimental procedures. This article presents predictive models of these properties developed using support vector machine (SVM) algorithm. The GFA and crystallization tendency were investigated by melt-quenching 131 drug molecules in situ using differential scanning calorimetry. The SVM algorithm was used to develop computational models based on calculated molecular descriptors. The analyses confirmed the previously suggested cutoff molecular weight (MW) of 300 for glass-formers, and also clarified the extent to which MW can be used to predict the GFA of compounds with MW < 300. The topological equivalent of Grav3_3D, which is related to molecular size and shape, was a better descriptor than MW for GFA; it was able to accurately predict 86% of the data set regardless of MW. The potential for crystallization was predicted using molecular descriptors reflecting Hückel pi atomic charges and the number of hydrogen bond acceptors. The models developed could be used in the early drug development stage to indicate whether amorphization would be a suitable formulation strategy for improving the dissolution and/or apparent solubility of poorly soluble compounds.
    • Correlation of copy number aberrations with clinico-pathological criteria in paediatric glial tumours

      Ward, Samantha; Hayward, Richard; Harkness, William; Phipps, Kim; Thompson, Dominic; Harding, Brian; Wilkins, Peter; Darling, John L.; Thomas, David G.; Warr, Tracy (Society for Neuro-Oncology and Duke University Press, 2003)
      Glial cell tumours represent the largest group of brain tumours in childhood and include astrocytoma (WHO grades I-IV) and ependymoma (WHO grade II-III). However, little is known about the pathogenesis of these tumours. We have used comparative genomic hybridisation (CGH) to investigate the genetic alterations in 128 tumours from children and young adults (< 30 years of age) comprising 52 ependymoma, including 40 samples that have previously been reported (44 grade II and 8 grade III) and 76 astrocytoma (consisting of 34 grade I, 17 grade II, 7 grade III, and 18 grade IV). Genetic alterations were compared to clinicopathological data such as histology, tumour recurrence, and survival in order to identify potential prognostic markers. In ependymoma, 39% of the tumours had no detectable copy number aberrations (CNAs). In the remaining tumours, the most common regions of gain were 4q (29%), 6q (21%), 1q (17%), and 2q (15%). The most common regions of loss were 22 (29%), 16p (17%), 17p (13%), and 20q (13%). Three regions of high copy number amplification were observed in 3 tumours at 1q24-31 (3 cases), 8q21-23 (3 cases), and 9p (1 case). There was no association between any CNA and histology, tumour recurrence, or length of survival. In contrast, in the astrocytoma group there was a clear association between histology and the presence of CNAs. The pattern of genetic alterations became increasingly complex with tumour grade, and grade IV tumours were more likely to have CNAs than lower grade tumours (p = 0.0502). Overall, the most frequent alterations observed in astrocytoma were gain of 4q (11%), loss 16p (10.5%), and loss 17p (10.5%). However, several CNAs were seen predominantly in grade IV tumours (gain 1q, 2q, 4q, and 5q). Fourteen amplicons were observed in 8 tumours of all grades, of which the most common were localised to 7q31 (4 cases), 8q21-22 (3 cases), 19p (2 cases), 2q (2 cases), and 12q15-21 (2 cases). From this study, it appears that paediatric glial tumours are much more genetically heterogeneous than their adult counterparts, and further molecular investigations are needed to define clinically useful subgroups.