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Grygielska B, Hughes CE, Watson SP. Molecular basis of platelet activation by an alphaIIbbeta3-CHAMPS peptide. J Thromb Haemost 2009; 7:339-46. [PMID: 19036072 DOI: 10.1111/j.1538-7836.2008.03228.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND A novel method, known as computed helical anti-membrane protein (CHAMP), for the design of peptides that bind with high affinity and selectivity to transmembrane helices was recently described and illustrated using peptides that bind alphaIIb- and alphav-integrin subunits, which induce selective activation of integrins alphaIIbbeta3 and alphavbeta3, respectively. OBJECTIVES In the present study, we have investigated the ability of an alphaIIb-CHAMPS peptide (termed integrin-activatory-peptide or IAP) to stimulate protein tyrosine phosphorylation and aggregation in human and mouse platelets. METHODS The ability of IAP to stimulate platelet aggregation and dense granule secretion was measured in washed preparations of human and mouse platelets. Samples were taken for measurement of tyrosine phosphorylation. RESULTS IAP stimulates robust tyrosine phosphorylation of the tyrosine kinase Syk and the FcR gamma-chain, but only weak phosphorylation of PLCgamma2. Aggregation to low but not high concentrations of IAP is reduced in the presence of the Src kinase inhibitor, PP1, or by inhibitors of the two feedback agonists, ADP and thromboxane A(2) (TxA(2)) suggesting that activation is reinforced by Src kinase-driven release of ADP and TxA(2). Unexpectedly, aggregation by IAP is only partially inhibited in human and mouse platelets deficient in integrin alphaIIbbeta3. Further, IAP induces partial aggregation of formaldehyde-fixed platelets. CONCLUSIONS The present study demonstrates that the alphaIIb-CHAMPS peptide induces platelet activation through integrin alphaIIbbeta3-dependent and independent pathways with the former mediating tyrosine phosphorylation of FcR gamma-chain and Syk. The use of the alphaIIb-CHAMPS peptide to study integrin alphaIIbbeta3 function is compromised by non-integrin-mediated effects.
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Hughes CE, Auger JM, McGlade J, Eble JA, Pearce AC, Watson SP. Differential roles for the adapters Gads and LAT in platelet activation by GPVI and CLEC-2. J Thromb Haemost 2008; 6:2152-9. [PMID: 18826392 PMCID: PMC2710801 DOI: 10.1111/j.1538-7836.2008.03166.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Accepted: 08/25/2008] [Indexed: 11/27/2022]
Abstract
BACKGROUND The adapter proteins SLP-76 and LAT have been shown to play critical roles in the activation of PLCgamma2 in platelets downstream of GPVI/FcRgamma and the C-type lectin receptor CLEC-2. SLP-76 is constitutively associated with the adapter Gads in platelets, which also binds to tyrosine phosphorylated LAT, thereby providing a potential pathway of regulation of SLP-76. OBJECTIVE In the present study, we have compared the role of Gads alongside that of LAT following activation of the major platelet glycoprotein receptors using mice deficient in the two adapter proteins. RESULTS Gads was found to be required for the efficient onset of aggregation and secretion in response to submaximal stimulation of GPVI and CLEC-2, but to be dispensable for activation following stronger stimulation of the two receptors. Gads was also dispensable for spreading induced through integrin alpha(IIb)beta(3) or the GPIb-IX-V complex. Further, Gads plays a negligible role in aggregate formation on collagen at an arteriolar rate of shear. In stark contrast, platelets deficient in the adapter LAT exhibit a marked decrease in aggregation and secretion following activation of GPVI and CLEC-2, and are unable to form stable aggregates on collagen at arteriolar shear. CONCLUSIONS The results demonstrate that Gads plays a key role in linking the adapter LAT to SLP-76 in response to weak activation of GPVI and CLEC-2 whereas LAT is required for full activation over a wider range of agonist concentrations. These results reveal the presence of a Gads-independent pathway of platelet activation downstream of LAT.
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Cao J, Li S, Shi Z, Yue Y, Sun J, Chen J, Fu Q, Hughes CE, Caterson B. Articular cartilage metabolism in patients with Kashin-Beck Disease: an endemic osteoarthropathy in China. Osteoarthritis Cartilage 2008; 16:680-8. [PMID: 17945513 DOI: 10.1016/j.joca.2007.09.002] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Accepted: 09/02/2007] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The objective of this study was to investigate CD44 and proteoglycan metabolism in patients suffering from Kashin-Beck Disease (KBD), an endemic osteoarthropathy that affects 2.5 million of 30 million people living in the KBD regions of China. METHODS Immunohistochemical analyses of cluster of differentiation-44 (CD44), BC-13 and 3-B-3(-) expression were performed in cartilage sections harvested from KBD and normal patients. In addition, the serum levels of soluble CD44 (sCD44), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase-1 were determined using a sandwich enzyme linked immunosorbent assay. RESULTS Hematoxylin & eosin and toluidine blue staining indicated that there was cell necrosis and proteoglycan loss in cartilage from both KBD children and adult cartilage. Strong immunohistochemical staining for CD44, BC-13 and 3-B-3(-) occurred in the majority of adult KBD patients and most KBD children. Furthermore, statistically significant elevated levels of sCD44, IL-1beta and TNF-alpha were found in the sera of both adult and child KBD patients when compared to the levels of normal adult and child controls. Interestingly, IL-1beta and TNF-alpha serum levels were all high in normal children from KBD regions when compared to normal children from non-KBD regions suggesting that unidentified factors (e.g., a genetic predisposition) may protect some people from KBD pathology. CONCLUSION Our results demonstrate that altered CD44, IL-1beta and TNF-alpha metabolism occurs in the pathogenesis of KBD and there is an increased aggrecanase-generated proteoglycan loss from KBD adult and child cartilage. These primary metabolic changes are likely to be significant contributing factor causing pathological joint formation and instability that leads to secondary osteoarthritis in KBD patients.
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Riba R, Hughes CE, Graham A, Watson SP, Naseem KM. Globular adiponectin induces platelet activation through the collagen receptor GPVI-Fc receptor gamma chain complex. J Thromb Haemost 2008; 6:1012-20. [PMID: 18419742 DOI: 10.1111/j.1538-7836.2008.02982.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The adipocyte-derived cytokine, adiponectin (Ad), exerts potent vascular effects, although the direct effects of Ad on blood platelets are unclear. OBJECTIVE The influence of globular Ad (gAd) on blood platelet function was investigated. RESEARCH DESIGN AND METHODS We measured platelet aggregation and tyrosine phosphorylation signaling events in human and mouse platelets. The ability of gAd to activate Glycoprotein VI (GPVI) activity was determined with a NFAT luciferase reporter assay. RESULTS gAd, but not full length Ad, induced rapid aggregation and granule secretion of human and mouse platelets through a pathway that is ablated under conditions of Src kinase inhibition, indicating a tyrosine kinase-dependent mechanism. Consistent with this, gAd stimulates rapid tyrosine phosphorylation of several proteins in human and mouse platelets. The pattern of increase in tyrosine phosphorylation was similar to that induced by collagen, with the tyrosine kinase Syk and PLCgamma2 being identified among the list of tyrosine phosphorylated proteins. As collagen activates platelet through the GPVI-Fc receptor gamma-chain (FcRgamma) complex, we used FcRgamma null platelets (which also lack GPVI) to explore the mechanism by which gAd stimulates platelets. Stimulation of tyrosine phosphorylation and platelet aggregation by gAd was abolished in FcRgamma null platelets and markedly reduced in the absence of PLCgamma2. Further, GPVI was confirmed as a collagen receptor for gAd by increased luciferase activity in Jurkat T-cells transfected with GPVI. CONCLUSIONS We identify gAd as a novel ligand for GPVI that stimulates tyrosine kinase-dependent platelet aggregation. Our data raise the possibility that gAd may promote unwanted platelet activation at sites of vascular injury.
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Gibson JJ, Sadek MA, Stone DJM, Hughes CE, Hankin S, Cendon DI, Hollins SE. Evaporative isotope enrichment as a constraint on reach water balance along a dryland river. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2008; 44:83-98. [PMID: 18320430 DOI: 10.1080/10256010801887489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Deuterium and oxygen-18 enrichment in river water during its transit across dryland region is found to occur systematically along evaporation lines with slopes of close to 4 in (2)H-(18)O space, largely consistent with trends predicted by the Craig-Gordon model for an open-water dominated evaporating system. This, in combination with reach balance assessments and derived runoff ratios, strongly suggests that the enrichment signal and its variability in the Barwon-Darling river, Southeastern Australia is acquired during the process of evaporation from the river channel itself, as enhanced by the presence of abundant weirs, dams and other storages, rather than reflecting inherited enrichment signals from soil water evaporation in the watershed. Using a steady-state isotope mass balance analysis based on monthly (18)O and (2)H, we use the isotopic evolution of river water to re-construct a perspective of net exchange between the river and its contributing area along eight reaches of the river during a drought period from July 2002 to December 2003, including the duration of a minor flow event. The resulting scenario, which uses a combination of climatological averages and available real-time meteorological data, should be viewed as a preliminary test of the application rather than as a definitive inventory of reach water balance. As expected for a flood-driven dryland system, considerable temporal variability in exchange is predicted. While requiring additional real-time isotopic data for operational use, the method demonstrates potential as a non-invasive tool for detecting and quantifying water diversions, one that can be easily incorporated within existing water quality monitoring activities.
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Hawkins JA, Boutaoui N, Cheung KY, Van Klinken RD, Hughes CE. Intercontinental dispersal prior to human translocation revealed in a cryptogenic invasive tree. THE NEW PHYTOLOGIST 2007; 175:575-587. [PMID: 17635232 DOI: 10.1111/j.1469-8137.2007.02125.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In this study, complementary species-level and intraspecific phylogenies were used to better circumscribe the original native range and history of translocation of the invasive tree Parkinsonia aculeata. Species-level phylogenies were reconstructed using three chloroplast gene regions, and amplified fragment length polymorphism (AFLP) markers were used to reconstruct the intraspecific phylogeny. Together, these phylogenies revealed the timescale of transcontinental lineage divergence and the likely source of recent introductions of the invasive. The sequence data showed that divergence between North American and Argentinean P. aculeata occurred at least 5.7 million years ago, refuting previous hypotheses of recent dispersal between North and South America. AFLP phylogenies revealed the most likely sources of naturalized populations. The AFLP data also identified putatively introgressed plants, underlining the importance of wide sampling of AFLPs and of comparison with uniparentally inherited marker data when investigating hybridizing groups. Although P. aculeata has generally been considered North American, these data show that the original native range of P. aculeata included South America; recent introductions to Africa and Australia are most likely to have occurred from South American populations.
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Fidopiastis CM, Stapleton CB, Whiteside JD, Hughes CE, Fiore SM, Martin GA, Rolland JP, Smith EM. Human Experience Modeler: context-driven cognitive retraining to facilitate transfer of learning. ACTA ACUST UNITED AC 2006; 9:183-7. [PMID: 16640476 DOI: 10.1089/cpb.2006.9.183] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
We describe a cognitive rehabilitation mixed-reality system that allows therapists to explore natural cuing, contextualization, and theoretical aspects of cognitive retraining, including transfer of training. The Human Experience Modeler (HEM) mixed-reality environment allows for a contextualized learning experience with the advantages of controlled stimuli, experience capture and feedback that would not be feasible in a traditional rehabilitation setting. A pilot study for testing the integrated components of the HEM is discussed where the participant presents with working memory impairments due to an aneurysm.
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Little CB, Flannery CR, Hughes CE, Goodship A, Caterson B. Cytokine induced metalloproteinase expression and activity does not correlate with focal susceptibility of articular cartilage to degeneration. Osteoarthritis Cartilage 2005; 13:162-70. [PMID: 15694578 DOI: 10.1016/j.joca.2004.10.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2004] [Accepted: 10/22/2004] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To determine whether the focal susceptibility to cartilage degeneration in joints is related to a differential response to cytokine stimulation. METHODS Compare aggrecan and collagen catabolism in in-vitro models of cartilage degradation induced by retinoic acid (RA), interleukin-1 (IL-1), tumor necrosis factor alpha (TNF) and IL-1 plus oncostatin M (OSM). Glycosaminoglycan (GAG) and hydroxyproline (HyPro) quantification and Western immunoblot analyses of aggrecan and collagen degradation products were undertaken in explant cultures of normal cartilage from regions of equine joints with a known high and low susceptibility to degeneration in disease. RNA isolation and semi quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis were performed to determine the expression of aggrecanases, matrix metalloproteinases (MMPs) and their inhibitors. RESULTS Although the rate of basal cartilage aggrecan turnover was dependent on joint region there was no difference in the response of different cartilages to cytokines. Individual animals did show a significant difference in the response of certain cartilages to cytokines, with both decreased and increased aggrecan loss in cartilage with a low susceptibility to degeneration. Aggrecan release in both short- and long-term cultures from all cartilages was associated with increased cleavage by aggrecanases rather than MMPs. There was a poor correlation between expression of aggrecanases, MMPs or their inhibitors and cytokine induced aggrecan catabolism. IL-1 alone was able to stimulate collagen breakdown in equine articular cartilage and surprisingly, significantly more collagen loss was induced in cartilage from regions less susceptible to degeneration. CONCLUSIONS Collectively, these studies suggest that a regional difference in response to catabolic cytokines is unlikely to be a factor in the initiation of focal cartilage degeneration in osteoarthritis (OA).
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Hughes CE, Airey PL, Duran EB, Miller BM, Sombrito E. Using radiotracer techniques for coastal hydrodynamic model evaluation. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2004; 76:195-206. [PMID: 15245848 DOI: 10.1016/j.jenvrad.2004.03.026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2003] [Revised: 12/15/2003] [Accepted: 12/29/2003] [Indexed: 05/24/2023]
Abstract
A three-dimensional (3D) water circulation and contaminant transport model of Manila Bay has been developed with the aim of better understanding the formation and movement of harmful algal blooms. Radiotracer techniques were used to evaluate the model by recording the dispersion of a tracer at depths of 2 and 15 m near the injection point. The selected tracer was 99mTc eluted from a molybdenum/technetium medical generator. The rationale for the choice of the tracer and the location of the injection is discussed. At 2 m the transport was dominated by the prevailing winds, and at 15 m by tidally induced currents. The development of the hydrodynamic model and its experimental evaluation were iterative processes. The experimental study confirmed the need for full 3D modelling of Manila Bay; quantified the impact of the prevailing wind field on contaminant dispersion near the injection point; and allowed the calculation of transverse dispersivity to guide the selection of parameter values used in the overall model.
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Dart AJ, Little CB, Hughes CE, Chu O, Dowling BA, Hodgson DR, Rose RJ, Johnson KA. Recombinant equine growth hormone administration: effects on synovial fluid biomarkers and cartilage metabolism in horses. Equine Vet J 2003; 35:302-7. [PMID: 12755435 DOI: 10.2746/042516403776148165] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
REASONS FOR PERFORMING STUDY Recombinant equine growth hormone (reGH) has recently been evaluated for effects on body condition and wound healing. It has the potential to influence articular cartilage via stimulation of IGF-1. OBJECTIVES To investigate effects of administration on synovial joint metabolism. METHODS Six mature horses were given 20 microg/kg bwt reGH daily for 8 weeks by i.m. injection. Three control horses were injected with sterile water. Serum and synovial fluid samples were collected at 6, 8, 11 and 16 weeks for GH and IGF-1 assays. Articular cartilage harvested at week 16 was evaluated by Western analysis using monoclonal antibodies BC-13, BC-4, 8-A-4 and CH-3. RESULTS Concentrations of IGF-1 in serum and synovial fluid were significantly elevated (P < 0.05) at 6 and 8 weeks in the reGH group. Glycosaminoglycan concentrations in synovial fluid were significantly less than controls at these time points, suggesting that reGH may modulate proteoglycan metabolism in articular cartilage. In the reGH group, there were not any alterations in synovial fluid content of 3B3(-) epitope or aggrecan metabolite, or in aggrecan or link protein catabolites retained within cartilage, that might be expected with development of osteoarthritis. CONCLUSIONS Intramuscular administration of reGH may be a more efficient means of delivery of IGF-1 to joints for cartilage resurfacing initiatives. POTENTIAL RELEVANCE We found no alterations in cartilage metabolism indicative of development of osteoarthritis.
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Hughes CE, Pratima R, Karlsson T, Levitt MH. Double-quantum solid-state NMR of 13C spin pairs coupled to 14N. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 159:25-35. [PMID: 12468300 DOI: 10.1016/s1090-7807(02)00118-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We examine the double-quantum magic angle spinning NMR spectra of pairs of 13C nuclei coupled to one or more 14N nuclei. The experimental spectra of 13C(2)-glycine and glycyl-[13C(2)]-glycyl-glycine are used to demonstrate the sensitivity of the spectra to the orientation of 14N quadrupole interaction tensors and to the molecular torsional angles.
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Dispaltro FL, Gingrass MK, Chang KN, Hughes CE. Correcting lipoplasty contour irregularities. Aesthet Surg J 2001; 21:435-40. [PMID: 19331926 DOI: 10.1067/maj.2001.119384] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Abstract
The worldwide search for the ideal soft tissue filler material continues. The authors focus on the stringent safety and efficacy requirements for soft tissue fillers and provide an overview of the current natural and synthetic materials. (Aesthetic Surg J 2001;21:469-471.).
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Abstract
BACKGROUND Previously published articles presenting rates for lipoplasty morbidity and mortality have reported on procedures performed before mid 1998. OBJECTIVE The present survey reports on morbidity and mortality for lipoplasty procedures performed by members of the American Society for Aesthetic Plastic Surgery (ASAPS) from September 1, 1998, through August 31, 2000. It assesses whether ASAPS-member surgeons have modified their lipoplasty practices in accordance with the 1998 recommendations of the Lipoplasty Task Force. METHODS In September 2000, ASAPS sent out a 4-page questionnaire to 1432 Active Members, all of whom were board-certified plastic surgeons. The survey included questions about complications and fatal outcomes associated with lipoplasty procedures, performance of combination procedures, patient selection, changes in lipoplasty and anesthesia techniques, and surgical facility accreditation. Completed surveys were anonymous and were mailed by respondents directly to an independent research firm for collation. Further data analysis was conducted by an independent statistician. RESULTS A total of 754 questionnaires were returned, for a response rate of 53%. ASAPS members reported on 94,159 lipoplasty procedures. In all, 66% of the procedures were lipoplasty only, 20% were lipoplasty without abdominoplasty but with one or more additional procedures, and 14% were lipoplasty with abdominoplasty, with or without any other procedures. The most frequently reported postoperative event was nausea/vomiting (1.02%, or 1 per 98 procedures). The most frequently reported major complication was skin slough (0.0903%, or 1 per 1107 procedures). In all, there were 245 major complications, for a rate of 0.2602%. Death associated with lipoplasty performed as an isolated procedure was rare; the mortality rate was 0.0021%, or 1 per 47,415 procedures. Stated positively, the estimated non-mortality probability is 99.98%. When lipoplasty was performed with other procedures, excluding abdominoplasty, the rate was 0.0137%, or 1 per 7314 procedures. When lipoplasty was combined with abdominoplasty, with or without other procedures, the rate was 0.0305%, or 1 per 3281 procedures[mdash ]a rate 14 times greater than that for lipoplasty only. Nearly 33% of respondents said that they had modified their approach to lipoplasty and/or their approach to patient selection within the last 24 months in accordance with published recommendations of the Lipoplasty Task Force. CONCLUSIONS The ASAPS survey documents the current safety of lipoplasty when it is performed as an isolated procedure by properly trained surgical specialists adhering to recommended standards of clinical practice. Further studies are needed to examine the factors that increase the risk in combined procedures as well as the effectiveness of prophylactic measures in avoiding complications.
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Karlsson T, Hughes CE, Schmedt auf der Günne J, Levitt MH. Double-quantum excitation in the NMR of spinning solids by pulse-assisted rotational resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2001; 148:238-247. [PMID: 11237629 DOI: 10.1006/jmre.2000.2243] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We describe a new technique for double-quantum excitation in magic-angle-spinning NMR of powdered solids. The technique is designed to efficiently excite double-quantum coherence in the vicinity of a rotational resonance condition. The offset from rotational resonance allows the double-quantum filtered signals to be observed with high resolution and sensitivity. The method uses rotational excitation of zero-quantum coherence, assisted by radiofrequency pulse cycles. The zero-quantum coherence is converted into double-quantum coherence by a frequency-selective inversion sequence. Experiments on [(13)C(2), (15)N]-glycine demonstrate a double-quantum filtering efficiency of approximately 41% at a sample rotation frequency of 8.300 kHz, which is 1.600 kHz away from the n = 1 rotational resonance. We achieve 32% double-quantum filtering efficiency at a spinning frequency of 9.250 kHz, which is 2.550 kHz away from rotational resonance.
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Flannery CR, Little CB, Hughes CE, Curtis CL, Caterson B, Jones SA. IL-6 and its soluble receptor augment aggrecanase-mediated proteoglycan catabolism in articular cartilage. Matrix Biol 2000; 19:549-53. [PMID: 11068209 DOI: 10.1016/s0945-053x(00)00111-6] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Elevated concentrations of interleukin-6 (IL-6) and soluble IL-6 receptor (sIL-6R) in the synovial fluids and serum of patients with arthritis have been implicated in the joint tissue destruction associated with these conditions, however studies conducted to date on the role and effects of IL-6 in the process of cartilage proteoglycan (aggrecan) catabolism are disparate. In the present study, bovine articular cartilage explants were maintained in a model organ culture system in the presence or absence of IL-1alpha or TNF-alpha, and under co-stimulation with or without IL-6 and/or sIL-6R. After measuring proteoglycan loss from the explants, the proteolytic activity and expression profiles of aggrecanase(s) was assessed for each culture condition. Stimulation of cartilage explants with IL-6 and/or sIL-6R potentiated aggrecan catabolism and release above that seen in the presence of IL-1alpha or TNF-alpha alone. This catabolism was associated with aggrecanase (but not MMP) activity, with correlative mRNA expression for aggrecanase-2.
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Rees SG, Flannery CR, Little CB, Hughes CE, Caterson B, Dent CM. Catabolism of aggrecan, decorin and biglycan in tendon. Biochem J 2000; 350 Pt 1:181-8. [PMID: 10926842 PMCID: PMC1221240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
We have examined the catabolism of the proteoglycans aggrecan, decorin and biglycan in fresh tendon samples and in explant cultures of tissue from the tensional and compressed regions of young and mature bovine tendons. A panel of well-characterized antibodies that recognize glycosaminoglycan or protein (linear or neoepitope) sequences was used to detect proteoglycans and proteoglycan degradation products that were both retained within the tissue and released into the culture medium. In addition, a reverse-transcriptase-mediated PCR analysis was used to examine the mRNA expression patterns of tendon proteoglycans and aggrecanases. The results of this study indicate a major role for aggrecanase(s) in the catabolism of aggrecan in bovine tendon. The study also provides a characterization of glycosaminoglycan epitopes associated with the proteoglycans of tendon, illustrating age-related changes in the isomers of chondroitin sulphate disaccharides that remain attached to the core protein glycosaminoglycan linkage region after digestion with chondroitinase ABC. Evidence for a rapid turnover of the small proteoglycans decorin and biglycan was also observed, indicating additional molecular pathways that might compromise the integrity of the collagen matrix and potentially contribute to tendon dysfunction after injury and during disease.
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Caterson B, Flannery CR, Hughes CE, Little CB. Mechanisms involved in cartilage proteoglycan catabolism. Matrix Biol 2000; 19:333-44. [PMID: 10963994 DOI: 10.1016/s0945-053x(00)00078-0] [Citation(s) in RCA: 220] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The increased catabolism of the cartilage proteoglycan aggrecan is a principal pathological process which leads to the degeneration of articular cartilage in arthritic joint diseases. The consequent loss of sulphated glycosaminoglycans, which are intrinsic components of the aggrecan molecule, compromises both the functional and structural integrity of the cartilage matrix and ultimately renders the tissue incapable of resisting the compressive loads applied during joint articulation. Over time, this process leads to irreversible cartilage erosion. In situ degradation of aggrecan is a proteolytic process involving cleavage at specific peptide bonds located within the core protein. The most well characterised enzymatic activities contributing to this process are engendered by zinc-dependent metalloproteinases. In vitro aggrecanolysis by matrix metalloproteinases (MMPs) has been widely studied; however, it is now well recognised that the principal proteinases responsible for aggrecan degradation in situ in articular cartilage are the aggrecanases, two recently identified isoforms of which are members of the 'A Disintegrin And Metalloproteinase with Thrombospondin motifs' (ADAMTS) gene family. In this review we have described: (i) the development of monoclonal antibody technologies to identify catabolic neoepitopes on aggrecan degradation products; (ii) the use of such neoepitope antibodies in studies designed to characterise and identify the enzymes responsible for cartilage aggrecan metabolism; (iii) the biochemical properties of soluble cartilage aggrecanase(s) and their differential expression in situ; and (iv) model culture systems for studying cartilage aggrecan catabolism. These studies have clearly established that 'aggrecanase(s)' is primarily responsible for the catabolism and loss of aggrecan from articular cartilage in the early stages of arthritic joint diseases that precede overt collagen catabolism and disruption of the tissue integrity. At later stages, when collagen catabolism is occurring, there is evidence for MMP-mediated degradation of the small proportion of aggrecan remaining in the tissue, but this occurs independently of continued aggrecanase activity. Furthermore, the catabolism of link proteins by MMPs is also initiated when overt collagen degradation is evident.
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Curtis CL, Hughes CE, Flannery CR, Little CB, Harwood JL, Caterson B. n-3 fatty acids specifically modulate catabolic factors involved in articular cartilage degradation. J Biol Chem 2000; 275:721-4. [PMID: 10625599 DOI: 10.1074/jbc.275.2.721] [Citation(s) in RCA: 202] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
This study describes specific molecular mechanisms by which supplementation with n-3 fatty acids (i.e. those present in fish oils) can modulate the expression and activity of degradative and inflammatory factors that cause cartilage destruction during arthritis. Our data show that incorporation of n-3 fatty acids (but not other polyunsaturated or saturated fatty acids) into articular cartilage chondrocyte membranes results in a dose-dependent reduction in: (i) the expression and activity of proteoglycan degrading enzymes (aggrecanases) and (ii) the expression of inflammation-inducible cytokines (interleukin (IL)-1alpha and tumor necrosis factor (TNF)-alpha) and cyclooxygenase (COX-2), but not the constitutively expressed cyclooxygenase COX-1. These findings provide evidence that n-3 fatty acid supplementation can specifically affect regulatory mechanisms involved in chondrocyte gene transcription and thus further advocate a beneficial role for dietary fish oil supplementation in alleviation of several of the physiological parameters that cause and propogate arthritic disease.
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Little CB, Flannery CR, Hughes CE, Mort JS, Roughley PJ, Dent C, Caterson B. Aggrecanase versus matrix metalloproteinases in the catabolism of the interglobular domain of aggrecan in vitro. Biochem J 1999; 344 Pt 1:61-8. [PMID: 10548534 PMCID: PMC1220614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
The importance of aggrecanase versus matrix metalloproteinase (MMP) enzymic activities in the degradation of aggrecan in normal and osteoarthritic (OA) articular cartilage in vitro was studied in order to further our understanding of the potential role of these two enzyme activities in aggrecan catabolism during the pathogenesis of cartilage degeneration. Porcine and bovine articular cartilage was maintained in explant culture for up to 20 days in the presence or absence of the catabolic stimuli retinoic acid, interleukin-1 or tumour necrosis factor-alpha. Release of proteoglycan from cartilage was measured as glycosaminoglycan (GAG) release using a colorimetric assay. Analysis of proteoglycan degradation products, both released into culture media and retained within the cartilage matrix, was performed by Western blotting using antibodies specific for the N- and C-terminal neoepitopes generated by aggrecanase- and MMP-related catabolism of the interglobular domain of the aggrecan core protein (IGD). In addition, studies determining the mRNA expression for MMP-3 and MMP-13 in these same cultures were undertaken. These analyses indicated that all three catabolic agents stimulated the release of >80% of the GAG from the articular cartilage over 4 days. The degree of GAG release corresponded to an increase in aggrecanase-generated aggrecan catabolites released into the media and retained within the cartilage. Importantly, there was no evidence for the release of MMP-generated aggrecan metabolites into the medium, nor the accumulation of MMP-generated catabolites within the tissue in these same cultures. Expression of the mRNAs for two MMPs known to be capable of degrading the aggrecan IGD, MMP-3 and MMP-13, was detected. However, increased expression of these MMPs was not correlated with aggrecan degradation. Analyses using porcine cartilage, cultured with or without catabolic stimulation for 12 h to 20 days, indicated that primary cleavage of the IGD by aggrecanase was responsible for release of aggrecan metabolites at both the early and late time points of culture. Cultures of late-stage OA human articular cartilage samples indicated that aggrecanase activity was upregulated in the absence of catabolic stimulation when compared with normal porcine or bovine cartilage. In addition, even in this late-stage degenerate cartilage, aggrecanase and not MMP activity was responsible for the release of the majority of aggrecan from the cartilage. This study demonstrates that the release of aggrecan from both normal and OA cartilage in response to catabolic stimulation in vitro involves a primary cleavage by aggrecanase and not MMPs.
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Flannery CR, Little CB, Hughes CE, Caterson B. Expression of ADAMTS homologues in articular cartilage. Biochem Biophys Res Commun 1999; 260:318-22. [PMID: 10403768 DOI: 10.1006/bbrc.1999.0909] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Articular chondrocytes possess the capacity to express a number of ADAM (A Disintegrin And Metalloproteinase) family members, thereby implicating a role for such proteins in the turnover of cartilage extracellular matrix molecules. Recently, the sequence for the human orthologue of an "aggrecanase" isolated from bovine nasal cartilage has been elucidated, and the recombinant protein product shown to be capable of cleaving aggrecan specifically at the relevant peptide bonds which are hydrolyzed in situ during cartilage degradation. The sequence for the human "aggrecanase" exhibits homology with that of murine ADAMTS-1, an ADAM with thrombospondin type I motifs. In the present study we have identified additional ADAMTS homologues and have examined their mRNA expression profiles in freshly excised human articular cartilage and in human cartilage explant cultures stimulated with IL-1, TNF-alpha, or retinoic acid, agents which enhance "aggrecanase" activity in vitro. Significantly, cartilage exposed to retinoic acid showed a marked increase in the release of "aggrecanase"-generated aggrecan catabolites with no concomitant increase in mRNA levels for any of the ADAMTS homologues investigated. These findings indicate that enhanced "aggrecanase" activity, which may be attributed to known ADAMTS homologues, may be predominantly regulated by post-transcriptional mechanism(s), and may raise the possiblility for the existence of other as yet unidentified "aggrecanase(s)."
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Flannery CR, Little CB, Caterson B, Hughes CE. Effects of culture conditions and exposure to catabolic stimulators (IL-1 and retinoic acid) on the expression of matrix metalloproteinases (MMPs) and disintegrin metalloproteinases (ADAMs) by articular cartilage chondrocytes. Matrix Biol 1999; 18:225-37. [PMID: 10429942 DOI: 10.1016/s0945-053x(99)00024-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The chondrocytes of articular cartilage synthesize a number of proteinases which are capable of degrading the component molecules of this specialized extracellular matrix. The use of class-specific proteinase inhibitors indicates that major activities responsible for catabolism of proteoglycan (aggrecan) and collagen are attributable to zinc-dependent metalloproteinases. In this study, we have compared the mRNA expression profiles of two matrix metalloproteinases (MMP-3 and MMP-13) and five disintegrin-metalloproteinases (ADAM-10, ADAM-9, ADAM-15, TNF-alpha-converting enzyme and decysin) by chondrocytes (human, porcine and bovine) from fresh cartilage and in cartilage explant cultures and isolated cells cultured in monolayer or in agarose gels. Such cultures were maintained in the presence or absence of interleukin-1 (IL-1) or all-trans-retinoic acid, two agents which promote cartilage matrix degradation in vitro. Whereas transcripts for all metalloproteinases examined were detected in chondrocytes from human osteoarthritic cartilage in monolayer cultures, mRNAs for ADAM-15 and decysin were not present in fresh osteoarthritic human cartilage or explant cultures. Similarly, expression of porcine and bovine metalloproteinase mRNAs varied with different culture conditions. Novel cDNA sequences obtained for porcine and bovine MMP-3 and MMP-13, porcine ADAM-10, porcine and bovine ADAM-9 and porcine TACE confirmed expression of mRNAs for these molecules by articular chondrocytes. Quantitative RT-PCR analysis was used to determine the effects of IL-1 and retinoic acid on metalloproteinase mRNA levels in human chondrocytes cultured in monolayer and in porcine chondrocytes cultured in agarose. For the MMPs, IL-1 treatment resulted in an approximately two to threefold increase in human and porcine MMP-3 and MMP-13 mRNAs, while retinoic acid treatment caused a statistically significant increase in human MMP-3 mRNA levels, but no significant change in transcript levels for porcine MMP-3 nor human or porcine MMP-13. The mRNA levels for ADAM-15 were elevated in human monolayer chondrocytes exposed to IL-1 or retinoic acid, while transcripts levels for TNF-alpha converting enzyme were increased in response to retinoic acid. In contrast, ADAM-9 mRNA levels were decreased in human monolayer chondrocytes exposed to IL-1 or retinoic acid. The results demonstrate that chondrocyte metalloproteinase expression can vary dependent on cell environment in situ and in vitro, and information on chondrocyte MMP and ADAM gene expression following cytokine (IL-1) or retinoid stimulation.
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Hughes CE. Patient selection, planning, and marking in ultrasound-assisted lipoplasty. Clin Plast Surg 1999; 26:279-82; ix. [PMID: 10327268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
The ideal ultrasound-assisted lipoplasty candidate differs little from the ideal candidate for traditional lipoplasty. This ideal candidate is within 20% of their ideal body weight (as determined by the insurance company statistics; i.e., 100 lbs for 5 feet in height, and 10 pounds for each inch above 5 feet). These patients were thought to be the only patients acceptable for lipoplasty when liposuction was first begun in the early 1980s. Innovative techniques, improved equipment, advances in superficial liposuction, syringe method, ultrasonic lipoplasty, external ultrasound assist, and other factors have served to expand the potential patient population greatly.
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Caterson B, Flannery CR, Hughes CE, Little CB. Mechanisms of proteoglycan metabolism that lead to cartilage destruction in the pathogenesis of arthritis. Drugs Today (Barc) 1999; 35:397-402. [PMID: 12973442 DOI: 10.1358/dot.1999.35.4-5.552213] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
The mechanisms and agents involved in cartilage matrix destruction are poorly understood and at present there are no means of therapeutic intervention that halt or slow the degradative processes that result in tissue loss, joint space narrowing and the eventual need for surgery with total joint replacement. In recent years our laboratory has pioneered the development and use of monoclonal antibody (MAb) technologies for the study of changes in cartilage matrix metabolism in health and disease. In this chapter we have summarized results coming from our recent studies examining the mechanisms of cartilage proteoglycan (aggrecan) catabolism that precedes cartilage destruction in arthritis. This research has used two approaches. The first is our access to a panel of MAbs that recognize both constitutive structural epitopes and catabolic neoepitopes on cartilage proteoglycan metabolites. These antibodies have allowed us to determine whether the unknown proteolytic agent 'aggrecanase' or known matrix metalloproteinases (MMPs) are involved in the increased aggrecan catabolism that is observed in arthritis. Secondly, we have used reverse transcription-polymerase chain reaction (RT-PCR) techniques to profile the expression of members of the MMP family or ADAMs (A disintegrin and metalloproteinase) that are potentially involved in this degenerative process. Collectively, these investigations have established that aggrecanase is the major proteolytic activity responsible for aggrecan loss in the early stages that lead to cartilage degradation in arthritis. In addition, our studies have allowed us to determine many important biochemical properties of aggrecanase without knowing the identity of the enzyme. Our data also calls into question the role that MMPs may play in the early stages of cartilage destruction that lead to surface fibrillation. However, MMPs may be involved in later stages where collagen degradation is prevalent. The role that ADAMs play is still unknown, although they are postulated to play an important role in shedding or activation of different classes of matrix proteases. Furthermore, we have observed changes in the patterns of cartilage expression in fresh tissue and model culture systems. This work has indicated clearly that there are several different classes of enzyme that can be targeted for innovative therapies which could slow or halt cartilage destruction in arthritis.
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Flannery CR, Hughes CE, Schumacher BL, Tudor D, Aydelotte MB, Kuettner KE, Caterson B. Articular cartilage superficial zone protein (SZP) is homologous to megakaryocyte stimulating factor precursor and Is a multifunctional proteoglycan with potential growth-promoting, cytoprotective, and lubricating properties in cartilage metabolism. Biochem Biophys Res Commun 1999; 254:535-41. [PMID: 9920774 DOI: 10.1006/bbrc.1998.0104] [Citation(s) in RCA: 241] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have performed cDNA sequencing and homology analyses to elucidate the complete amino acid composition for a superficial zone protein (SZP) from human and bovine cartilage which has previously been shown to be a proteoglycan specifically synthesized by chondrocytes located at the surface of bovine articular cartilage and also some synovial lining cells. The results of this study indicate that cartilage SZP is homologous with a glycoprotein first described as the precursor protein of a megakaryocyte stimulating factor (MSF). Sequence comparisons and analyses indicate that (i) the amino acid composition of SZP is highly conserved between bovine and human species, (ii) SZP contains structural motifs at the N- and C-termini which are similar to those found in vitronectin and which may impart cell-proliferative and matrix-binding properties to the molecule, and (iii) SZP contains large and small mucin-like repeat domains composed of the sequences KEPAPTTT/P (76-78 repeats) and XXTTTX (6-8 repeats), respectively, which occur within a large central region of approximately 940 amino acids. The mucin-like domains are likely to be substituted with O-linked oligosaccharides which would impart lubricating properties to SZP which in part accumulates at the articular cartilage-synovial fluid interface. Additionally, we have shown that interleukin-1 inhibits the biosynthesis of chondrocyte SZP, while TGF-beta and IGF-1 increase its biosynthesis, and that in pathological (osteoarthritic) human articular cartilage SZP mRNA can be expressed as an alternatively spliced variant lacking exons 4 and 5 which encode a potential heparin binding domain. The occurrence of different SZP alternative splice variants and the differential expression of SZP in the presence of cytokines and growth factors suggest that SZP may play an important cytoprotective role by preventing cellular adhesion to the articular cartilage surface in normal cartilage metabolism. Modifications to the structure of SZP, coupled with inhibition of SZP synthesis during inflammation, may account for the attachment and invasion of pannus observed in inflammatory joint diseases.
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