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Botelho CM, Brooks RA, Spence G, McFarlane I, Lopes MA, Best SM, Santos JD, Rushton N, Bonfield W. Differentiation of mononuclear precursors into osteoclasts on the surface of Si-substituted hydroxyapatite. J Biomed Mater Res A 2006; 78:709-20. [PMID: 16739170 DOI: 10.1002/jbm.a.30726] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In healthy bone, resorption and synthesis are in perfect coordination. In previous studies we demonstrated that the incorporation of silicon into the hydroxyapatite (HA) lattice enhances the proliferation and differentiation of human osteoblasts. Therefore, the aim of this study was to demonstrate the effect of silicon-substituted HA (0.8 and 1.5 wt % Si-HA) on the differentiation of mononuclear cells into osteoclasts, using two different starting cultures, peripheral blood mononuclear cells (PBMC) and monocytes expressing the CD14 antigen (CD14+). Through this study, it was possible to demonstrate that Si-HA allows the differentiation of mononuclear cells into mature osteoclasts, independent of the starting culture, PBMC or CD14+. Most of the cells on the surface of the materials expressed osteoclastic markers: actin rings, several nuclei, positivity for tartrate-resistant acid phosphatase (TRAP), and vitronectin receptor. In the presence of osteoclasts, a higher release of calcium and phosphate into the medium from the 1.5 wt % Si-HA substrate was detected when compared to the HA substrate; therefore, these results indicate higher osteoclastic resorptive activity on the 1.5 wt % Si-HA surface. Si-HA can be resorbed by cellular mechanisms and have a stimulatory effect on osteoclasts, although the underlying mechanism is still poorly understood.
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Affiliation(s)
- C M Botelho
- INEB-Instituto de Engenharia Biomédica, Laboratório de Biomateriais, Rua do Campo Alegre, 823, 4150-180 Porto, Portugal
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Savage DB, Soos MA, Powlson A, O'Rahilly S, McFarlane I, Halsall DJ, Barroso I, Thomas EL, Bell JD, Scobie I, Belchetz PE, Kelly WF, Schafer AJ. Familial partial lipodystrophy associated with compound heterozygosity for novel mutations in the LMNA gene. Diabetologia 2004; 47:753-6. [PMID: 15298354 DOI: 10.1007/s00125-004-1360-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Gurnell EM, Thomas SK, McFarlane I, Munday I, Balan KK, Berman L, Chatterjee VKK, Wishart GC. Focused parathyroid surgery with intraoperative parathyroid hormone measurement as a day-case procedure. Br J Surg 2004; 91:78-82. [PMID: 14716798 DOI: 10.1002/bjs.4463] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND This study assessed the feasibility, efficacy and safety of focused parathyroidectomy combined with intraoperative parathyroid hormone (IOPTH) measurement in a day-case setting. METHODS Over 28 months 50 consecutive patients (mean age 63 (range 33-92) years) with clear evidence of unifocal disease on sestamibi scanning or ultrasonography underwent unilateral neck exploration via a small lateral incision. Blood samples for measurement of IOPTH were taken at induction of anaesthesia, before adenoma excision and after adenoma excision (at 5, 10 and 20 min). Ten patients were discharged within 23 h and 40 patients on the day of surgery. RESULTS A solitary adenoma was identified in all but one patient, with a mean operating time of 30 (range 16-57) min. After parathyroidectomy, IOPTH levels fell appropriately except in one patient with multiglandular hyperplasia. No patient developed symptomatic hypocalcaemia during the 2 weeks after operation, enabling cessation of oral supplements. All patients remained normocalcaemic on follow-up (mean 26 (range 8-84) weeks) and histological examination confirmed parathyroid adenoma (48 patients), hyperplasia (one) or carcinoma (one). CONCLUSION After accurate preoperative localization of uniglandular disease, patients with primary hyperparathyroidism may be managed successfully and safely by focused parathyroidectomy with IOPTH measurement as a day-case procedure.
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Affiliation(s)
- E M Gurnell
- Department of Medicine, Addenbrooke's Hospital, Cambridge, UK
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Georgopoulou N, McLaughlin M, McFarlane I, Breen KC. The role of post-translational modification in beta-amyloid precursor protein processing. Biochem Soc Symp 2002:23-36. [PMID: 11447837 DOI: 10.1042/bss0670023] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The beta-amyloid precursor protein (APP) plays a pivotal role in the early stages of neurodegeneration associated with Alzheimer's disease. An alteration in the processing pattern of the protein results in an increase in the generation of the 40-42-amino-acid beta-amyloid (A beta) peptide, which coalesces to form insoluble, extracellular amyloid deposits. A greater understanding of the factors that influence APP processing may assist in the design of effective therapeutic agents to halt progression of Alzheimer's disease. APP is a sialoglycoprotein with two potential N-linked glycosylation sites, one of which may contain a complex oligosaccharide chain. An alteration in the glycosylation state of APP by the generation of oligomannosyl oligosaccharides results in a decrease in the secretion of the neuroprotective, soluble form of the protein and a parallel increase in the deposition of the cellular protein within the perinuclear region of the cell. Conversely, the attachment of additional terminal sialic acid residues on to the oligosaccharide chain results in an increase in secretion of soluble APP (sAPP alpha). One factor that has been widely reported to alter APP processing is the activation of protein kinase C (PKC). This process has been characterized using synaptosomal preparations, which suggests that the PKC action is occurring at the level of the plasma membrane. Furthermore, when cells are transfected with the sialyltransferase enzyme, there is a direct relationship between the sialylation potential of APP and the fold stimulation of sAPP alpha, after PKC activation. These results suggest that the post-translational modification of APP by glycosylation is a key event in determining the processing of the protein.
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Affiliation(s)
- N Georgopoulou
- Department of Pharmacology and Neuroscience, University of Dundee, Ninewells Hospital Medical School, Dundee DD1 9SY, U.K
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Dalziel M, Whitehouse C, McFarlane I, Brockhausen I, Gschmeissner S, Schwientek T, Clausen H, Burchell JM, Taylor-Papadimitriou J. The relative activities of the C2GnT1 and ST3Gal-I glycosyltransferases determine O-glycan structure and expression of a tumor-associated epitope on MUC1. J Biol Chem 2001; 276:11007-15. [PMID: 11118434 DOI: 10.1074/jbc.m006523200] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In breast cancer, the O-glycans added to the MUC1 mucin are core 1- rather than core 2-based. We have analyzed whether competition by the glycosyltransferase, ST3Gal-I, which transfers sialic acid to galactose in the core 1 substrate, is key to this switch in MUC1 glycosylation that results in the expression of the cancer-associated SM3 epitope. Of the three enzymes known to convert core 1 to core 2, by the addition of GlcNAc to GalNAc in core1 C2GnT1 is the dominant enzyme expressed in normal breast tissue. Expression of C2GnT1 is low or absent in around 50% of breast cancers, whereas expression of ST3Gal-I is consistently increased. Mapping of ST3Gal-I and C2GnT1 within the Golgi pathway showed some overlap. To examine functional competition, the enzymes were overexpressed in T47D cells, which normally make core 1-based structures, have no detectable C2GnT1 activity and express the SM3 epitope. Overexpression of C2GnT1 resulted in loss of binding of SM3 to MUC1, accompanied by a decrease in the GalNAc/GlcNAc ratio, indicative of a switch to core 2 structures. Transfection of a C2GnT1 expressing line with ST3Gal-I restored SM3 binding and reduced GlcNAc incorporation into MUC1 O-glycans. Thus, even when C2GnT1 is expressed, the O-glycans added to MUC1 become core 1-dominated structures, provided expression of ST3Gal-I is increased as it is in breast cancer.
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Affiliation(s)
- M Dalziel
- Imperial Cancer Research Fund, Breast Cancer Biology Group, 3rd Floor, Thomas Guy House, Guy's Hospital, London SE1 9RT, United Kingdom
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McFarlane I, Breen KC, Di Giamberardino L, Moya KL. Inhibition of N-glycan processing alters axonal transport of synaptic glycoproteins in vivo. Neuroreport 2000; 11:1543-7. [PMID: 10841374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Synaptic glycoproteins are synthesized and glycosylated in the neuronal cell body, and conveyed to terminals by fast axonal transport. We used the alpha-mannosidase inhibitor, 2-deoxymannojirimycin (dMan), to investigate the effects of disrupting N-glycan processing on the axonal trafficking of proteins in vivo. dMan significantly reduced rapid axonal transport in retinal ganglion cells to about 34% of control values 4h after metabolic labeling; at 8 h post-labeling the inhibition was reversed. 2-D gel analysis showed that dMan completely inhibited the arrival of radiolabeled L1 and NCAM at axon terminals, and resulted in the appearance of two novel proteins of 230 kDa and 155 kDa. Our results show that disruption of the N-glycosylation pathway has an immediate inhibitory effect on total axonal transport and longer lasting effects on the trafficking of specific glycoproteins to axon terminals in vivo.
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Affiliation(s)
- I McFarlane
- Department of Pharmacology and Neuroscience, University of Dundee, Ninewells Hospital Medical School, Scotland, UK
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Abstract
The lectins Sambucus nigra agglutinin (SNA) and Ricinus communis agglutinin (RCA), specific for alpha2,6 linked sialylation, and terminal galactose respectively were used to study the occurrence, linkage and distribution of human immunoglobulin G (IgG) sialylation. SNA was shown to bind N-glycan alpha2,6-linked sialic acid only. Sialidase analysis confirmed that this is the dominant, if not exclusive linkage. Total IgG sialylation was estimated at 1.0 microg SA/mg IgG (or about 0.5 mole per mole) using a biochemical sialic acid assay. SNA displayed strong binding to the IgG Fab fragment in both its native and denatured state. In contrast, SNA failed to bind the IgG Fc fragment in its native form, but displayed strong binding after the Fc was denatured. This allowed the construction of quantitative assays capable of measuring both IgG Fab and Fc alpha2,6-sialylation without the need for enzymatic peptide digestion.
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Affiliation(s)
- M Dalziel
- ICRF Breast Cancer Biology Group, Thomas Guy House, Guy's Hospital, London, UK.
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McFarlane I, Georgopoulou N, Coughlan CM, Gillian AM, Breen KC. The role of the protein glycosylation state in the control of cellular transport of the amyloid beta precursor protein. Neuroscience 1999; 90:15-25. [PMID: 10188930 DOI: 10.1016/s0306-4522(98)00361-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The amyloid beta precursor protein can exist as both a membrane-bound and a secreted protein, with the former having the potential to generate the amyloid beta peptide present in the neuritic plaques which are characteristic of Alzheimer's disease. In this study, we have used a clone of the AtT20 mouse pituitary cell line which expresses high levels of the amyloid beta precursor protein to characterize the glycosylation state of the secreted and membrane-bound forms of the protein and to examine the role of post-translational modifications in protein processing. Lectin blot analysis of immunoprecipitated amyloid beta precursor protein demonstrated that the soluble form of the protein contains significant amounts of sialic acid, with the lectin staining being reduced in the particulate cellular fractions. Treatment of the cells with mannosidase inhibitors to interfere with the formation of complex-type N-linked glycans resulted in a decrease in secreted amyloid beta precursor protein and an increase in the level of the cellular form of the protein. The increase in amyloid beta precursor protein levels in the cellular fraction was accompanied by an increase in perinuclear staining. Furthermore, cells overexpressing the alpha2,6(N)-sialyltransferase enzyme also demonstrated an increase in amyloid beta precursor protein secretion. These results suggest that the presence of terminal sialic acid residues on complex-type N-glycans may be required for the optimal transport of the amyloid beta precursor protein from the Golgi to the cell membrane with the subsequent cleavage to generate the secreted form of the protein.
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Affiliation(s)
- I McFarlane
- Neurosciences Institute, Department of Pharmacology and Neuroscience, University of Dundee, Ninewells Hospital Medical School, UK
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Gillian AM, McFarlane I, Lucy FM, Overly C, McConlogue L, Breen KC. Individual isoforms of the amyloid beta precursor protein demonstrate differential adhesive potentials to constituents of the extracellular matrix. J Neurosci Res 1997; 49:154-60. [PMID: 9272638 DOI: 10.1002/(sici)1097-4547(19970715)49:2<154::aid-jnr4>3.0.co;2-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The amyloid beta precursor protein (AbetaPP) can exist as a membrane-bound glycoprotein which modulates neural cell adhesion. The adhesion of clones of the AtT20 mouse pituitary cell line, transfected with cDNA coding for the 695 (AbetaPP695) and 751 (AbetaPP751) amino acid forms of the protein, to individual components of the extracellular matrix was determined using a centrifugal shear assay. On laminin, poly-L-lysine, fibronectin, and uncoated glass substrata, the cells transfected with AbetaPP695 (6A1 cells) demonstrated a 50% increase in adhesivity over nontransfected cells, while those transfected with AbetaPP751 (7A1 cells) showed a significant decrease in adhesion. There was, however, a significant increase in the adhesive strength of the 7A1 cells to collagen type IV with no change in the adhesivity of the 6A1 cells when compared with control. These changes in adhesivity could be attributed to changes in the levels of the membrane-bound protein and were not due to the interaction of soluble AbetaPP with elements of the extracellular matrix. These studies provide evidence for differential adhesivities of the constituent AbetaPP isoforms and the possible role of the Kunitz protease inhibitor (KPI) domain in influencing the adhesive properties of the protein backbone.
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Affiliation(s)
- A M Gillian
- Neurosciences Institute, Department of Pharmacology and Clinical Pharmacology, University of Dundee, Ninewells Hospital Medical School, Scotland
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Silva E, Sallie R, Tibbs C, McFarlane I, Johnson P, Williams R. Absence of hepatitis C virus in British patients with type 1 autoimmune chronic active hepatitis--a polymerase chain reaction and serological study. J Hepatol 1993; 19:211-5. [PMID: 8301054 DOI: 10.1016/s0168-8278(05)80573-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Despite several studies from continental Europe reporting a high prevalence of antibodies to the hepatitis C virus (HCV), there has been little evidence of such infection in patients from the United Kingdom. The use of the polymerase chain reaction combined with two separate second generation anti-HCV assays is reported here in 58 UK patients with well-documented autoimmune chronic active hepatitis. All patients were in corticosteroid induced remission. All sera were collected prospectively for the specific purpose of this study. HCV-RNA was not detected by use of the polymerase chain reaction in any of the patients and antibodies to HCV were only detected in one patient. No evidence was found for the involvement of the hepatitis C virus in UK patients with classical, corticosteroid sensitive autoimmune chronic active hepatitis.
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Affiliation(s)
- E Silva
- Institute of Liver Studies, King's College School of Medicine and Dentistry, London, UK
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