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Biomedical subjects

R W Ward

Publications and source records attributed to R W Ward.

At least 19 recordsLinked to original sources
PubMed2003

TGF-beta1 causes airway fibrosis and increased collagen I and III mRNA in mice.

BACKGROUND: Subepithelial collagen and extracellular matrix protein deposition are important pathophysiological components of airway remodelling in chronic asthma. Animal models based on the local reaction to antigens show structural alterations in the airway submucosal region and provide important information regarding disease pathophysiology. We describe a murine model of peribronchial fibrosis using intratracheally instilled transforming growth factor (TGF)-beta(1) in BALB/C mice that facilitates a mechanistic approach to understanding the cellular and molecular pathways leading to airway fibrosis. METHODS: BALB/C mice were intratracheally instilled with either TGF-beta(1) or buffered saline. Airway fibrosis was assessed by light microscopy, hydroxyproline content, and polymerase chain reaction (PCR) for collagen I and III on microdissected airway samples. The lysyl oxidase inhibitor beta-aminoproprionitrile (BAPN) was administered to TGF-beta(1) treated mice to block airway collagen deposition. Airway hyperresponsiveness was also measured after treatment with TGF-beta(1). RESULTS: During the 7 days after administration of TGF-beta(1) the mice developed increased subepithelial collagen which could be blocked by BAPN. Increased mRNAs for collagen types I and III were seen in microdissected airways 1 week after TGF-beta(1), and significantly increased total collagen was found in the airways 4 weeks after TGF-beta(1). A detectable increase in airway hyperreactivity occurred. CONCLUSIONS: This new model should facilitate detailed study of airway remodelling that occurs in the absence of detectable cellular inflammation, and allow examination of the functional consequences of a major structural alteration in the conducting airways uncomplicated by inflammatory cell influx.

Aminopropionitrile↗
PubMed2000

Selective small molecule inhibitors of glycogen synthase kinase-3 modulate glycogen metabolism and gene transcription.

BACKGROUND: Glycogen synthase kinase-3 (GSK-3) is a serine/threonine protein kinase, the activity of which is inhibited by a variety of extracellular stimuli including insulin, growth factors, cell specification factors and cell adhesion. Consequently, inhibition of GSK-3 activity has been proposed to play a role in the regulation of numerous signalling pathways that elicit pleiotropic cellular responses. This report describes the identification and characterisation of potent and selective small molecule inhibitors of GSK-3. RESULTS: SB-216763 and SB-415286 are structurally distinct maleimides that inhibit GSK-3alpha in vitro, with K(i)s of 9 nM and 31 nM respectively, in an ATP competitive manner. These compounds inhibited GSK-3beta with similar potency. However, neither compound significantly inhibited any member of a panel of 24 other protein kinases. Furthermore, treatment of cells with either compound stimulated responses characteristic of extracellular stimuli that are known to inhibit GSK-3 activity. Thus, SB-216763 and SB-415286 stimulated glycogen synthesis in human liver cells and induced expression of a beta-catenin-LEF/TCF regulated reporter gene in HEK293 cells. In both cases, compound treatment was demonstrated to inhibit cellular GSK-3 activity as assessed by activation of glycogen synthase, which is a direct target of this kinase. CONCLUSIONS: SB-216763 and SB-415286 are novel, potent and selective cell permeable inhibitors of GSK-3. Therefore, these compounds represent valuable pharmacological tools with which the role of GSK-3 in cellular signalling can be further elucidated. Furthermore, development of similar compounds may be of use therapeutically in disease states associated with elevated GSK-3 activity such as non-insulin dependent diabetes mellitus and neurodegenerative disease.

Adenosine Triphosphate↗
PubMed1999

The inhibition of human cytomegalovirus (hCMV) protease by hydroxylamine derivatives.

Aryl hydroxylamine derivatives have been synthesised that are some of the most potent inhibitors of hCMV protease prepared to date (IC50 14-60 nM). Mass spectrometry studies indicate that oxazinone derived hydroxylamines inhibit the enzyme by acylation of Ser132 whereas non-oxazinone derived hydroxylamines appear to inhibit via formation of a sulfinanilide at Cys138.

Amino Acid Sequence↗
PubMed1998

The contribution of classical (beta1/2-) and atypical beta-adrenoceptors to the stimulation of human white adipocyte lipolysis and right atrial appendage contraction by novel beta3-adrenoceptor agonists of differing selectivities.

The role of beta3- and other putative atypical beta-adrenoceptors in human white adipocytes and right atrial appendage has been investigated using CGP 12177 and novel phenylethanolamine and aryloxypropanolamine beta3-adrenoceptor (beta3AR) agonists with varying intrinsic activities and selectivities for human cloned betaAR subtypes. The ability to demonstrate beta1/2AR antagonist-insensitive (beta3 or other atypical betaAR-mediated) responses to CGP 12177 was critically dependent on the albumin batch used to prepare and incubate the adipocytes. Four aryloxypropanolamine selective beta3AR agonists (SB-226552, SB-229432, SB-236923, SB-246982) consistently elicited beta1/2AR antagonist-insensitive lipolysis. However, a phenylethanolamine (SB-220646) that was a selective full beta3AR agonist elicited full lipolytic and inotropic responses that were sensitive to beta1/2AR antagonism, despite it having very low efficacies at cloned beta1- and beta2ARs. A component of the response to another phenylethanolamine selective beta3AR agonist (SB-215691) was insensitive to beta1/2AR antagonism in some experiments. Because no [corrected] novel aryloxypropanolamine had a beta1/2AR antagonist-insensitive inotropic effect, these results establish more firmly that beta3ARs mediate lipolysis in human white adipocytes, and suggest that putative 'beta4ARs' mediate inotropic responses to CGP 12177. The results also illustrate the difficulty of predicting from studies on cloned betaARs which betaARs will mediate responses to agonists in tissues that have a high number of beta1- and beta2ARs or a low number of beta3ARs.

Adipose Tissue↗
PubMed1997

Structure-based design of substituted diphenyl sulfones and sulfoxides as lipophilic inhibitors of thymidylate synthase.

Six new diphenyl sulfoxide and five new diphenyl sulfones were designed, synthesized, and tested for their inhibition of human and Escherichia coli thymidylate synthase (TS) and of the growth of cells in tissue culture. The best sulfoxide inhibitor of human TS was 3-chloro-N-((3,4-dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl)-4- (phenylsulfinyl)-N-(prop-2-ynyl)-aniline (7c) that had a Ki of 27 nM. No sulfone improved on TS inhibition by the previously reported 4-(N-((3,4-dihydro-2-methyl-6-quinazolinyl)methyl)-N-prop-2- ynylamino)phenyl phenyl sulfone (Ki = 12 nM). Nevertheless, one sulfone, 4-((2-chlorophenyl)sulfonyl)-N-((3,4-dihydro-2-methyl-4-oxo-6- quinazolinyl)methyl)-N-(prop-2-ynyl)aniline, was selected, on the basis of its inhibition of both TS and cell growth, for antitumor testing; it gave a 61% increase in life span to mice bearing the thymidino kinase-deficient L5178Y (TK-) lymphoma. A crystal structure of N-((3,4-dihydro-2-methyl-4-oxo-6-quinazolinyl)methyl)-4-((2- methylphenyl)sulfinyl)-N-(prop-2-ynyl)aniline complexed with E. coli TS was solved and revealed selective binding of one sulfoxide enantiomer. AMBER calculations showed that the enantioselection was due to asymmetric electrostatic effects at the mouth of the active site. In contrast, a similar crystal structure of the sulfoxide 7c, along with AMBER calculations, indicated that both enantiomers bound, but with different affinities. The side chain of Phe176 shifted in order to structurally accommodate the chlorine of the more weakly bound enantiomer.

Animals↗
PubMed1996

Structure-based design of lipophilic quinazoline inhibitors of thymidylate synthase.

To develop novel lipophilic thymidylate synthase (TS) inhibitors, the X-ray structure of Escherichia coli TS in ternary complex with FdUMP and the inhibitor 10-propargyl-5,8-dideazafolic acid (CB3717) was used as a basis for structure-based design. A total of 31 novel lipophilic TS inhibitors, lacking a glutamate residue, were synthesized; 26 of them had in common a N-((3,4-dihydro-2-methyl-6-quinazolinyl)methyl)-N-prop-2-ynylaniline+ ++ structure in which the aniline was appropriately substituted with simple lipophilic substituents either in position 3 or 4, or in both. Compounds were tested for their inhibition of E. coli TS and human TS and also for their inhibition of the growth in tissue culture of a murine leukemia, a human leukemia, and a thymidine kinase-deficient human adenocarcinoma. The crystal structures of five inhibitors complexed with E. coli TS were determined. Five main conclusions are drawn from this study. (i) A 3-substituent such as CF(3), iodo, or ethynyl enhances binding by up to 1 order of magnitude and in the case of CF(3) was proven to fill a nearby pocket in the enzyme. (ii) A simple strongly electron-withdrawing substituent such as NO(2) or CF(3)SO(2) in the 4-position enhances binding by 2 orders of magnitude; it is hypothesized that the transannular dipole so induced interacts favorably with the protein. (iii) Attempts to combine the enhancements of i and ii in the same molecule were generally unsuccessful (iv) A 4-C(6)H(5)SO(2) substituent provided both electron withdrawal and a van der Waal's interaction of the phenyl group with a hydrophobic surface at the mouth of the active site. The inhibition (K(is) = 12 nM) of human TS by this compound, 7n, showed that C(6)H(5)SO(2) provided virtually as much binding affinity as the CO-glutamate which it had replaced. (v) The series of compounds were poorly water soluble, and also the potent TS inhibition shown by several of them did not translate into good cytotoxicity. Compounds with large cyclic groups linked to position 4 by an SO or SO(2) group did, however, have IC(50)'s in the range 1-5 microM. Of these, 4-(N-((3,4-dihydro-2-methyl-6-quinazolinyl)methyl)-N-prop-2-ynylamino )phenyl phenyl sulfone, 7n, had IC(50)'s of about 1 microM and was chosen for further elaboration.

Adenocarcinoma↗
PubMed1995

Digital clubbing. Demonstration with positron emission tomography.

Digital clubbing is a classic cutaneous manifestation of pulmonary disease, but its mechanism is unknown. We describe a patient with lung cancer and clubbing in whom positron emission tomography (PET) demonstrated, for the first time, that increased glucose metabolism occurs at the nailbed. PET may contribute to future investigations of digital clubbing.

Carcinoma, Squamous Cell↗
PubMed1994

Synthesis of novel N-phosphonoalkyl dipeptide inhibitors of human collagenase.

The synthesis of a series of N-phosphonalkyl dipeptides 6 is described. Syntheses were devised that allowed the preparation of single diastereoisomers and the assignment of stereochemistry. The compounds were evaluated in vitro for their ability to inhibit the degradation of radiolabeled collagen by purified human lung fibroblast collagenase. Several of the compounds were potent collagenase inhibitors and were at least 10-fold more potent than their corresponding N-carboxyalkyl analogues. Activity was lost when the phosphonic acid group P(O)(OH)2 was replaced by the phosphinic acid groups P(O)(H)(OH) and P(O)(Me)(OH). At the P1 position, (R)- or (S)-alkyl groups, especially ethyl and methyl (e.g., 12a,b, 52a,b, and 53a,b), or an (R)-phenethyl moiety (55a) conferred high potency (IC50 values in the range 0.23-0.47 microM). (S)-Stereochemistry was preferred for the P1' isobutyl side chain. Structure-activity relationships were also investigated at the P2' site, and interestingly, compounds with basic side chains, such as the guanidine 57a, were equipotent with more lipophilic compounds, such as 52a. As with other series of collagenase inhibitors, potency was enhanced by introducing bicyclic aromatic P2' substituents. The most potent phosphonic acid of the series was the bicyclic aromatic P2' tryptophan analogue 59a (IC50 0.05 microM).

Animals↗
PubMed1992

Characterization of a Cold-Regulated Wheat Gene Related to Arabidopsis cor47.

The cDNA clone pWG1 represents a gene, designated cor39, from Triticum aestivum L. cv Winoka (a winter wheat) that is related to a cold-regulated Arabidopsis thaliana L. (Heyn) gene, cor47. In vitro transcription/translation experiments in conjunction with DNA sequence analysis indicated that cor39 encodes a hydrophilic polypeptide of 39 kD (isoelectric point of 7.5), designated COR39. The polypeptide is composed primarily of two sequences, each of which is repeated six times. One sequence, which is lysine rich, occurs in COR47 (the polypeptide encoded by Arabidopsis cor47) and group II LEA proteins, polypeptides hypothesized to have roles in desiccation and drought tolerance (J. Baker, C. Steele, L. Dure III [1988] Plant Mol Biol 11: 277-291). The second sequence, which is glycine rich, occurs in some, but not all, group II LEA proteins. Southern analysis indicated that wheat has a number of loci related to cor39. Transcripts of about 3.3, 1.5, and 0.8 kb that hybridize with cor39 were found to accumulate in leaf, root, and crown tissues of cold-acclimated plants; they accumulated rapidly in response to low temperature and returned quickly to low levels when plants were returned to normal growth temperature. Transcripts hybridizing with cor39 were present at relatively high levels in wheat seeds and accumulated in plants in response to exogenous application of ABA and water stress. The similarities in expression of wheat and Arabidopsis cor genes and possible functional relationships among COR39, COR47, and LEA proteins are discussed.

Journal Article↗
PubMed1986

7-Aroyl-2,3-dihydrobenzo[b]furan-3-carboxylic acids and 7-benzoyl-2,3-dihydrobenzo[b]thiophene-3-carboxylic acids as analgesic agents.

The synthesis of a series of 7-aroyl-2,3-dihydrobenzo[b]furan-3-carboxylic acids and 7-benzoyl-2,3-dihydrobenzo[b]thiophene-3-carboxylic acids is described. The isomeric 4-benzoyl-1,3-dihydrobenzo[c]furan-1-carboxylic acid was also prepared. Compounds were evaluated for analgesic activity in the mouse phenyl-p-quinone-induced writhing test. Selected compounds were tested for their ability to produce gastric damage in fasted mice and for inhibition of prostaglandin synthetase activity in vitro. Zomepirac was used as a reference. Structure-activity relationships are discussed. One of the compounds, 7-benzoyl-5-chloro-2,3-dihydrobenzo[b]furan-3-carboxylic acid (2c), combined potent analgesic activity with low gastric irritancy.

Analgesics↗