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Boyle MS, Bennett M, Keogh GW, O'Brien M, Flynn G, Collins DW, Biharih D. Central venous Oxygen Saturation during High-Risk General Surgical Procedures—Relationship to Complications and Clinical Outcomes. Anaesth Intensive Care 2019; 42:28-36. [DOI: 10.1177/0310057x1404200107] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- M. S. Boyle
- Intensive Care Unit and Wales Anaesthesia, Prince of Wales Hospital, Randwick, New South Wales
| | - M. Bennett
- Intensive Care Unit and Wales Anaesthesia, Prince of Wales Hospital, Randwick, New South Wales
- Wales Anaesthesia and University of New South Wales, Prince of Wales Hospital, Randwick, New South Wales
| | - G. W. Keogh
- Intensive Care Unit and Wales Anaesthesia, Prince of Wales Hospital, Randwick, New South Wales
- Department of Surgery
| | - M. O'Brien
- Intensive Care Unit and Wales Anaesthesia, Prince of Wales Hospital, Randwick, New South Wales
| | - G. Flynn
- Intensive Care Unit and Wales Anaesthesia, Prince of Wales Hospital, Randwick, New South Wales
| | - D. W. Collins
- Intensive Care Unit and Wales Anaesthesia, Prince of Wales Hospital, Randwick, New South Wales
| | - D. Biharih
- Intensive Care Unit and Wales Anaesthesia, Prince of Wales Hospital, Randwick, New South Wales
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2
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Flynn G, Stokes K, Ryan KM. Low temperature solution synthesis of silicon, germanium and Si–Ge axial heterostructures in nanorod and nanowire form. Chem Commun (Camb) 2018; 54:5728-5731. [DOI: 10.1039/c8cc03075h] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Herein, we report the formation of silicon, germanium and more complex Si–SixGe1−x and Si–Ge axial 1D heterostructures, at low temperatures in solution. The incorporation of a reducing agent into the reaction is shown to be effective to lower precursor decomposition temperatures.
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Affiliation(s)
- G. Flynn
- Bernal Institute and Department of Chemical Sciences
- University of Limerick
- Ireland
| | - K. Stokes
- Bernal Institute and Department of Chemical Sciences
- University of Limerick
- Ireland
| | - K. M. Ryan
- Bernal Institute and Department of Chemical Sciences
- University of Limerick
- Ireland
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3
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Nixon C, Flynn G, Murphy M, Fenlason L, Shields S. Cultural relevancy in capacity building: Community education to address
the malnutrition spectrum. Ann Glob Health 2015. [DOI: 10.1016/j.aogh.2015.02.611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
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4
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Hensman D, Wild E, Robertson N, Farmer R, Scahil R, Haider S, Tessari M, Flynn G, Fischer D, Macdonald D, Tabrizi S. D01 Quantification Of Huntingtin Species In Huntington's Disease Patient Leukocytes Using Electrochemiluminescence Immunoassays. Journal of Neurology, Neurosurgery & Psychiatry 2014. [DOI: 10.1136/jnnp-2014-309032.93] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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5
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Chao LL, Cargill GS, Kothandaraman C, Cyr D, Flynn G, Hellman ES, Wiesmann D, Buchanan DNE, Brener I. Nonuniform Morphology and Luminescence Properties of a Molecular Beam Epitaxy GaN Film from Atomic Force Microscopy, Scanning Electron Microscopy and Cathodoluminescence. ACTA ACUST UNITED AC 2014. [DOI: 10.1557/s1092578300001332] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Complex faceted features of micrometer sizes and with intense luminescence rise 200-300 nm above the surface of a GaN thin film grown by molecular beam epitaxy on (0001) sapphire. Cathodoluminescence measurements at room temperature and at 8K were used to investigate the luminescence properties of these microfeatures in comparison with those of the background GaN material. The morphology of the micro-features was studied by scanning electron microscopy and by atomic force microscopy.GaN and related compounds have been considered as promising materials for light emitting devices in the short wavelength visible and UV spectral regions because of their direct, wide band gaps and high luminescence efficiency. Remarkable, rapid success has been achieved in developing devices based on III-V nitrides, which allows these material systems to rival other systems under development [1]. Blue-green LEDs fabricated from InGaN/AlGaN double-heterostructure layers on sapphire substrates by Nichia Chemical Industries in Japan are commercially available, despite the presence of high extended defect densities in the 1010 /cm2 range [2]. In December 1995, an important milestone in the development of nitride lasers was reached; Nakamura et al. in Nichia demonstrated the first nitride-based laser diode which operated at 417 nm under pulsed conditions at room temperature [3].The morphology and spatial distribution of luminescence in GaN thin films have been investigated by several research groups [4], [5], [6], although most efforts have been directed to developing appropriate growth conditions for improved film quality. From observations by scanning electron microscopy (SEM) and atomic force microscopy (AFM), Trager-Cowan et al. described an MBE-grown GaN film which contained an assembly of oriented hexagonal crystallites rising above a background of polycrystalline or amorphous material [4]. All the crystallites, oriented in a similar fashion, had roughly the same sizes, 1 or 2 μm across a hexagonal face and about 1 μm high. These crystallites were much brighter than the surrounding background material in panchromatic low-temperature cathodoluminescence (CL) images. Trager-Cowan et al. concluded that the crystallites were of better quality than the background material. They also observed a green emission band, attributed to impurities, which became weaker for higher electron beam voltages, generating luminescence from deeper in the film. From this observation, they concluded that higher quality material is located closer to the film's outer surface. Spatial variation of the luminescence efficiency from MOCVD-grown films has also been observed by Ponce et al[5]. in their room-temperature CL microscopy studies. Their results showed significant nonuniformities in both the band-edge and yellow band emissions. Although they reported no faceted island structures, one of their samples had “marked surface features” and consisted of hexagonal crystals 10 to 50 μm in diameter. The crystals gave strong band-to-band (364 nm) luminescence.In this paper, the morphology of a GaN film grown on (0001) sapphire by MBE is characterized by SEM and AFM, and CL measurements are used to investigate the luminescence properties of the film at room temperature and at 8K. Some regions of this film are similar to the one described by Trager-Cowan et al. [4] in having micron sized, brightly luminescent islands. The hexagonal facet angles and bright luminescence of islands in our film also resemble the larger scale, more regularly shaped hexagonal crystals of Ponce et al. [5]. These regions lie on the boundary of excess gallium growth conditions. Our results differ from those of Trager-Cowan in terms of the island morphologies and the spectral character of luminescence from the islands and from the background material. Possible causes of the large variations in luminescence efficiency are discussed.
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6
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Iyer A, Gao L, Hicks M, Kumarasinghe G, Jansz P, Jabbour A, Al-Soufi S, Aneman A, Flynn G, Rajamani A, Cheng A, Raper R, Goh D, MacPartlin M, Saul P, Dhital K, Macdonald P. Case Report of Cardiac Allografts Retrieved From Human Donation After Circulatory Death (DCD) Donors - Assessment on Ex Vivo Beating Heart Perfusion Device. J Heart Lung Transplant 2014. [DOI: 10.1016/j.healun.2014.01.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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7
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Lee QY, Chan GSH, Redmond SJ, Middleton PM, Steel E, Malouf P, Critoph C, Flynn G, O'Lone E, Lovell NH. Classification of low systemic vascular resistance using photoplethysmogram and routine cardiovascular measurements. Annu Int Conf IEEE Eng Med Biol Soc 2011; 2010:1930-3. [PMID: 21097214 DOI: 10.1109/iembs.2010.5628062] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Low systemic vascular resistance (SVR) can be a useful indicator for early diagnosis of critical pathophysiological conditions such as sepsis, and the ability to identify low SVR from simple and noninvasive physiological signals is of immense clinical value. In this study, an SVR classification system is presented to recognize the occurrence of low SVR, among a heterogenous group of patients (N = 48), based on the use of routine cardiovascular measurements and features extracted from the finger photoplethysmogram (PPG) as inputs to a quadratic discriminant classifier. An exhaustive feature search was performed to identify a near optimum feature subset. Cohen's kappa coefficient (κ) was used as a performance measure to compare candidate feature sets. The classifier using the following combination of features performed best (κ = 0.56, sensitivity = 96.30%, positive predictivity = 92.31%): normalized low-frequency power (LFNU) derived from PPG, ratio of low-frequency power to high-frequency power (LF/HF) of the PPG variability signal, and the ratio of mean arterial pressure to heart rate (MAP/HR). Classifiers that used either LF(NU) (κ = 0.43), LF/HF (κ = 0.37) or MAP/HR (κ = 0.43) alone showed inferior performance. Discrimination of patients with and without low SVR can be achieved with reasonable accuracy using multiple features derived from the PPG combined with routine cardiovascular measurements.
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Affiliation(s)
- Qim Y Lee
- Biomedical Systems Laboratory, School of Electrical Engineering and Telecommunications, the University of New South Wales, Sydney, 2052, Australia
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8
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Boyle M, Lau A, Nicholson L, O'Brien M, Flynn G, Collins D, Walsh W, Bihari D. Paracetamol-induced skin blood flow and blood pressure changes. Crit Care 2011. [PMCID: PMC3067019 DOI: 10.1186/cc9765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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9
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Stolyarova E, Stolyarov D, Bolotin K, Ryu S, Liu L, Rim KT, Klima M, Hybertsen M, Pogorelsky I, Pavlishin I, Kusche K, Hone J, Kim P, Stormer HL, Yakimenko V, Flynn G. Observation of graphene bubbles and effective mass transport under graphene films. Nano Lett 2009; 9:332-7. [PMID: 19105652 DOI: 10.1021/nl803087x] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Mechanically exfoliated graphene mounted on a SiO2/Si substrate was subjected to HF/H(2)O etching or irradiation by energetic protons. In both cases gas was released from the SiO2 and accumulated at the graphene/SiO2 interface resulting in the formation of "bubbles" in the graphene sheet. Formation of these "bubbles" demonstrates the robust nature of single layer graphene membranes, which are capable of containing mesoscopic volumes of gas. In addition, effective mass transport at the graphene/SiO2 interface has been observed.
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Affiliation(s)
- E Stolyarova
- Department of Chemistry and Nanoscale Science and Engineering Center, Columbia University, New York, New York 10027, USA
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10
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Boyle M, Steel E, Murgo M, Flynn G, O'Brien M, Lawrence J, Bihari D. Incidence of low central venous oxygen saturation after standard postoperative intensive care management. Crit Care 2007. [PMCID: PMC4095356 DOI: 10.1186/cc5463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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11
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Alexander D, Boord P, Brown K, Das P, Flynn G, Galletly C, Gordon E, Harris A, Williams L, Wong W. First-episode psychosis and direction of wave propagation at 1 Hz in the EEG. Acta Neuropsychiatr 2006; 18:240. [PMID: 27397156 DOI: 10.1111/j.1601-5215.2006.00158.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | - P Boord
- Brain Dynamics Centre, Westmead Millenium Institute and University of Sydney, Sydney,Australia
| | - K Brown
- Brain Dynamics Centre, Westmead Millenium Institute and University of Sydney, Sydney,Australia
| | - P Das
- Brain Dynamics Centre, Westmead Millenium Institute and University of Sydney, Sydney,Australia
| | - G Flynn
- Early Psychosis Intervention Program, Liverpool Hospital, NSW,Australia
| | - C Galletly
- Department of Psychiatry, University of Adelaide, SA,Australia
| | - E Gordon
- Brain Resource Company, Sydney,Australia
| | - A Harris
- The University of Sydney, Sydney,Australia
| | - L Williams
- Brain Dynamics Centre, Westmead Millenium Institute and University of Sydney, Sydney,Australia
| | - W Wong
- Early Psychosis Intervention Program, Liverpool Hospital, NSW,Australia
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12
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Hillyer P, Mordelet E, Flynn G, Male D. Chemokines, chemokine receptors and adhesion molecules on different human endothelia: discriminating the tissue-specific functions that affect leucocyte migration. Clin Exp Immunol 2004; 134:431-41. [PMID: 14632748 PMCID: PMC1808903 DOI: 10.1111/j.1365-2249.2003.02323.x] [Citation(s) in RCA: 135] [Impact Index Per Article: 6.8] [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: 01/16/2023] Open
Abstract
The selective accumulation of different leucocyte populations during inflammation is regulated by adhesion molecules and chemokines expressed by vascular endothelium. This study examined how chemokine production and the expression of adhesion molecules and chemokine receptors vary between endothelia from different vascular beds. Human saphenous vein endothelium was compared with lung and dermal microvascular endothelia and with umbilical vein endothelium and a bone-marrow endothelial cell line. All endothelia produced CCL2 and CXCL8 constitutively, whereas CXCL10 and CCL5 were only secreted after tumour necrosis factor (TNF)-alpha or interferon (IFN)-gamma stimulation. In combination with TNF-alpha, IFN-gamma suppressed CXCL8 but enhanced CCL5 and CXCL10, whereas transforming growth factor (TGF)-beta reduced secretion of all chemokines. Basal chemokine secretion was higher from umbilical vein than other endothelial cells. Chemokine receptors, CXCR1, CXCR3 and CCR3, were present on all endothelia but highest on saphenous vein. CCR4, CCR5, CCR6, CXCR2, CXCR4 and CXCR5 were also detected at variable levels on different endothelia. The variation between endothelia in chemokine secretion was much greater than the variations in adhesion molecules, both on resting cells and following cytokine stimulation. These results indicate that it is the tissue-specific variations in endothelial chemokine secretion rather than variations in adhesion molecules that can explain the different patterns of inflammation and leucocyte traffic seen in non-lymphoid tissues.
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Affiliation(s)
- P Hillyer
- Department of Biological Sciences, The Open University, Milton Keynes, UK
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13
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Hadgraft J, Goosen C, du Plessis J, Flynn G. Predicting the dermal absorption of thalidomide and its derivatives. Skin Pharmacol Physiol 2003; 16:123-9. [PMID: 12637788 DOI: 10.1159/000069028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2002] [Accepted: 08/06/2002] [Indexed: 11/19/2022]
Abstract
Concern has been expressed about the ability of simple algorithms to predict skin permeability and hence skin flux. For a series of thalidomide analogues, a number of software packages have been used to predict octanol water partition coefficients. These, in conjunction with molecular weight, have then been used to calculate skin permeability coefficients. These compare favourably with experimental values. Some of the software packages also predict aqueous solubilities, which can be subsequently used to calculate maximum skin flux. The predicted and measured solubilities have been compared together with the maximum fluxes. The results show that software can be used to predict octanol water partition coefficients and aqueous solubilities (more accurately if the melting point of the compound is known) and hence to obtain very reasonable estimates of skin permeation parameters. These are useful in predicting which analogue has the most appropriate properties for dermal delivery; in the case of the thalidomide analogues, it is the methyl-substituted compound that is best.
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Affiliation(s)
- J Hadgraft
- Medway Sciences, NRI, University of Greenwich, Chatham Maritime, UK.
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14
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Piatak DM, Flynn G, Yim K, Roosenberg J. Observations on bromine rearrangement during demethylation of bromomethoxybenzoic acids. J Org Chem 2002. [DOI: 10.1021/jo00426a029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Rahman S, Flynn G, Aitken A, Patel Y, Hussain F, Lu X, Loftus JC, French D, Wijelath E, Strand K, Savidge GF. Differential recognition of snake venom proteins expressing specific Arg-Gly-Asp (RGD) sequence motifs by wild-type and variant integrin alphaIIbbeta3: further evidence for distinct sites of RGD ligand recognition exhibiting negative allostery. Biochem J 2000; 345 Pt 3:701-9. [PMID: 10642531 PMCID: PMC1220807] [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: 02/15/2023]
Abstract
Several studies have demonstrated that the amino acid residues flanking the Arg-Gly-Asp (RGD) sequence of high-affinity ligands modulate their specificity of interaction with integrin complexes. Because of the absence of structural data for integrin complexes with bound ligand, the molecular basis for this specificity modulation remains obscure. In a previous paper [Rahman, Lu, Kakkar and Authi (1995) Biochem. J. 312, 223-232] we demonstrated that two genetically distinct venom-derived RGD proteins, kistrin and dendroaspin (both containing the sequence PRGDMP), were simple competitors, indicating the recognition of an identical binding site on the alpha(IIb)beta(3) complex. Furthermore, both kistrin and dendroaspin inhibited the binding of the disintegrin elegantin (containing the sequence ARGDNP) via a non-competitive mechanism, suggesting that the binding of elegantin to the alpha(IIb)beta(3) complex was at a remote site and down-regulated via an allosteric mechanism. Here we present further evidence for distinct RGD ligand recognition sites on the alpha(IIb)beta(3) complex that exhibit a negative allosteric relationship. A panel of well-characterized recombinant dendroaspin and elegantin derivatives were employed for this study. These recombinant molecules were constructed as glutathione S-transferase fusion proteins with either an Ala or Pro residue N-terminal to the RGD sequence in combination with either a Met or an Asn residue immediately C-terminal. Equilibrium competition experiments showed that elegantin binding to ADP-treated platelets was inhibited by derivatives Eleg. AM (ARGDMP) and Eleg. PM (PRGDMP) via an allosteric competitive mechanism, providing direct evidence that modulation of the RGD motif can alter competitive behaviour. In addition, recombinant kistrin and dendroaspin both inhibited elegantin binding via a non-competitive mechanism, confirming our previous observations. Further evidence for distinct binding sites employing an independent approach was obtained by analysing the binding of the panel of venom proteins to the functionally defective heterodimer alpha(IIb)beta(3) Ser(123)-->Ala expressed on Chinese hamster ovary cells. These studies demonstrated that simple competitors kistrin and dendroaspin bound with high affinity to the variant integrin complex. In contrast, the binding of elegantin and most significantly, recombinant Dendro. PN (PRGDNP) and Dendro. AN (ARGDNP) were abolished. These observations, taken together, are consistent with a model depicting the presence of distinct sites of RGD ligand recognition on the alpha(IIb)beta(3) complex that show the preferential recognition of specific RGD motifs. Competition experiments demonstrate a negative allosteric relationship between these RGD recognition sites.
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Affiliation(s)
- S Rahman
- The Coagulation Research Laboratory, GKT Medical School, St. Thomas' Hospital, Lambeth Palace Road, London SE1 7EH, U.K.
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Abstract
A method is described whereby a sequence of X-ray images at closely spaced photon energies is acquired using a scanning transmission X-ray microscope, and aligned. Near-edge absorption spectra can then be obtained both from large, irregular regions, and from regions as small as the spatial resolution of the microscope (about 40 nm in the examples shown here). The use of the technique is illustrated in examination of a layered polymer film, a micrometeorite section, and an interplanetary dust particle section.
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Affiliation(s)
- C Jacobsen
- Department of Physics and Astronomy, State University of New York at Stony Brook 11794-3800, USA.
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Jarrell JF, Denham E, Flynn G. When hospital files get in media hands. CMAJ 1999; 161:527-8. [PMID: 10497608 PMCID: PMC1230581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023] Open
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18
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Alhaq A, Mitchell M, Sethi M, Rahman S, Flynn G, Boulton P, Caeno G, Smith M, Savidge G. Identification of a novel mutation in a non-Jewish factor XI deficient kindred. Br J Haematol 1999; 104:44-9. [PMID: 10027710 DOI: 10.1046/j.1365-2141.1999.01150.x] [Citation(s) in RCA: 25] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The role of factor XI (FXI) in blood coagulation has been clarified in recent years by descriptions of FXI-deficient patients who are prone to excessive bleeding after haemostatic challenge. We have studied a large kindred of an Italian FXI-deficient patient with a previously undescribed mutation. The propositus, a 68-year-old woman, presented with a cerebral thromboembolic event but had no history of bleeding (FXI activity 1.6 U/dl). A sensitive ELISA failed to detect FXI antigen in the propositus. Sequence analysis of the entire FXI gene revealed a TGG to TGC transversion in codon 228 of exon 7 (FXI-W228C). This missense mutation results in a Trp to Cys substitution within the third apple domain of FXI. We conclude that this novel mutation occurred in a structurally conserved region and may therefore have interfered with either chain folding and secretion or stability of FXI and was responsible for the inherited abnormality seen in this kindred. It is unclear why this kindred does not exhibit a bleeding tendency but it may correlate with a FXI-like antigen and factor IX binding activity expressed on platelets.
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Affiliation(s)
- A Alhaq
- The Haemophilia Centre, St Thomas' Hospital, London, UK
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19
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Rahman S, Aitken A, Flynn G, Formstone C, Savidge GF. Modulation of RGD sequence motifs regulates disintegrin recognition of alphaIIb beta3 and alpha5 beta1 integrin complexes. Replacement of elegantin alanine-50 with proline, N-terminal to the RGD sequence, diminishes recognition of the alpha5 beta1 complex with restoration induced by Mn2+ cation. Biochem J 1998; 335 ( Pt 2):247-57. [PMID: 9761721 PMCID: PMC1219776 DOI: 10.1042/bj3350247] [Citation(s) in RCA: 37] [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: 01/27/2023]
Abstract
Several recent studies have demonstrated that the amino acid residues flanking the RGD sequence of high-affinity ligands modulate their specificity of interaction with integrin complexes. The present study has addressed the role of the residues flanking the RGD sequence in regulating the recognition by disintegrin of the alphaIIb beta3 and alpha5beta1 complexes by construction of a panel of recombinant molecules of Elegantin (the platelet aggregation inhibitor from the venom of Trimerasurus elegans) expressing specific RGD sequence motifs. Wild-type Elegantin (ARGDNP) and several variants including Eleg. AM (ARGDMP), Eleg. PM (PRGDMP) and Eleg. PN (PRGDNP) were expressed as glutathione S-transferase (GST) fusion proteins in Escherichia coli. The inhibitory efficacies of the panel of Elegantin variants were analysed in platelet adhesion assays with substrates immobilized with fibrinogen and fibronectin. Elegantin molecules containing an Ala residue N-terminal to the RGD sequence (wild-type Elegantin and Eleg. AM) showed strong inhibitory activity towards alphaIIbbeta3-dependent platelet adhesion on fibronectin, whereas a Pro residue in this position (Eleg. PM and Kistrin, the inhibitor from the venom of Calloselasma rhodostoma) engendered lower activity. The decreased activity could not be attributed to a decrease in the affinity of the disintegrin for the alphaIIb beta3 complex because both Eleg. AM and Eleg. PM had similar Kd (app) values. In contrast, Elegantin molecules into which a Met residue was introduced in place of the Asn residue C-terminal to the RGD sequence showed 10-13-fold elevated inhibitory activity towards platelet adhesion on fibrinogen and this was maintained with either a Pro or Ala residue N-terminal to the RGD sequence. In experiments with the alpha5 beta1 complex on K562 cells, the inhibitory efficacies of the panel of Elegantin molecules were analysed under two different cation conditions. First, in the presence of Ca2+/Mg2+, K562 cell adhesion on fibronectin was inhibited equally well by Elegantin and Eleg. AM but inhibited poorly by Eleg. PM and Kistrin. In contrast with platelets, the decreased inhibitory efficacy of the PRGDMP disintegrins was due to poor recognition of the alpha5 beta1 complex. In the presence of Mn2+ cation, K562 cell adhesion on fibrinogen was observed in an alpha5 beta1-dependent manner. Under these conditions both PRGD and ARGD containing disintegrins were strong inhibitors of K562 cell adhesion on fibrinogen and this was due to a markedly improved recognition of the alpha5 beta1 complex by the PRGD molecules. These observations demonstrate the pivotal role of the amino acids flanking the RGD sequence for disintegrin recognition of integrin complexes and highlight the subtle nature by which integrin-ligand binding specificity can be modulated by both cation and adhesive motif.
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Affiliation(s)
- S Rahman
- The Coagulation Research Laboratory, Division of Internal Medicine, United Medical and Dental School of Guy's, King's and St Thomas' Hospitals (GKT), St. Thomas' Campus, Lambeth Palace Road, London SE1 7EH, UK.
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Van Buskirk GA, González MA, Shah VP, Barnhardt S, Barrett C, Berge S, Cleary G, Chan K, Flynn G, Foster T, Gale R, Garrison R, Gochnour S, Gotto A, Govil S, Gray VA, Hammar J, Harder S, Hoiberg C, Hussain A, Karp C, Llanos H, Mantelle J, Noonan P, Zrebe H. Scale-up of adhesive transdermal drug delivery systems. Pharm Res 1997; 14:848-52. [PMID: 9244139 DOI: 10.1023/a:1012135430056] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- G A Van Buskirk
- Novartis Pharmaceuticals Corp., East Hanover, New Jersey 07936, USA.
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Abstract
In a recent report we described the effects of combined electroactivation and photoactivation of hematoporphyrin derivative (HPD) on human erythrocytes and established that activation-induced cell lysis was more pronounced when both modes of activation were sequentially applied to the system. Here we demonstrate that electric field-induced activation of HPD-treated HeLa cells results in cell death. This effect is shown to be dependant on both electric field strength and on HPD concentration. In addition, we demonstrate that exposure of HPD-treated cells to short and intense electric pulses prior to photoactivation, results in increased cell mortality. The results confirm our earlier suggestion that HPD may be activated in the presence of an applied electric field. The results further suggest that activation of photosensitizers using combined exposure to electric fields and light may play an important role in increasing the efficiency of photodynamic therapy (PDT) in the treatment of cancer.
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Affiliation(s)
- T Ward
- School of Applied Biological and Chemical Sciences, University of Ulster, Coleraine, UK
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22
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Barnicoat AJ, Wang Q, Turk J, Green E, Mathew CG, Flynn G, Buckle V, Hirst M, Davies K, Bobrow M. Clinical, cytogenetic, and molecular analysis of three families with FRAXE. J Med Genet 1997; 34:13-7. [PMID: 9032643 PMCID: PMC1050840 DOI: 10.1136/jmg.34.1.13] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [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: 02/03/2023]
Abstract
The probe StB12.3 has been used to screen the FMR-1 gene in 42 pedigrees with a distal Xq fragile site for expansion of the CCG repeat and aberrant methylation of the FRAXA locus. Four families did not have a FRAXA mutation and were investigated further. Fluorescent in situ hybridisation (FISH) and molecular analyses showed that three of these families had an expansion at FRAXE and one at FRAXE. Detailed psychiatric, psychological, and behavioural features of three families with FRAXE identified in the study are presented. All the males who expressed FRAXE had a large methylated CCG repeat at FRAXF. All males with the mutation had some degree of mental handicap. This study illustrates the need for the FRAXE phenotype to be defined further.
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Affiliation(s)
- A J Barnicoat
- Department of Medical and Molecular Genetics, Guy's Hospital, London, UK
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23
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Abstract
In this study it has been found that exposure of photosensitized erythrocytes to short, intense electric pulses, resulted in cell lysis. When erythrocytes were photosensitized with increasing concentrations of the photosensitizer, hematoporphyrin derivative (HPD), and subjected to electric pulses in the absence of light, cell lysis increased with increasing photosensitizer concentration. In addition, it has been shown that exposure of photosensitized erythrocytes to electric field pulses of increasing field strength resulted in increased cell lysis. Light activation of photosensitized erythrocytes, pre-treated with electric pulses, also resulted in increased cell lysis. The results presented here suggest that HPD may be activated in the absence of light using electric pulses. We suggest that enhancement of activation by electric field stimulation may find application in increasing the overall efficiency of photodynamic therapy.
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Affiliation(s)
- T Ward
- Biotechnology Research Group, School of Applied Biological and Chemical Sciences, University of Ulster, Coleraine, Co. Londonderry, Northern Ireland, UK
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24
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Rollan A, Ward T, Flynn G, McKerr G, McHale L, McHale AP. Use of real-time confocal laser scanning microscopy to study immediate effects of photodynamic activation on photosensitized erythrocytes. Cancer Lett 1996; 101:165-9. [PMID: 8620465 DOI: 10.1016/0304-3835(96)04150-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [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: 01/31/2023]
Abstract
With a view towards the design of systems capable of combining the use of chemotherapy and photodynamic therapy in the treatment of cancer and other disorders, it has been proposed that photosensitized erythrocytes might be employed as carriers/vehicles for agents such as cancer chemotherapeutics. In studying the light dependent release of entrapped agents from such a system, the efficacy of light induced release is usually studied by measuring release of an entrapped component into centrifugation supernatants following photoactivation. It has hitherto been extremely difficult to examine what occurs upon immediate irradiation at the microscopic level in real-time. In this study we demonstrate that, using real-time confocal laser scanning microscopy, it is possible to directly observe immediate short-term events occurring during direct irradiation with the visualizing beam. Following irradiation of photosensitized erythrocytes with the visualizing beam form the confocal scanning system, it was noticed that some from of cell-disruptive event occurred. In this study we demonstrate a dose dependent response between this relatively immediate, light induced disruptive event with respect to both irradiation exposure and photosensitizer concentration. We suggest that this system may provide a novel means of observing, at a microscopic level, events occurring in real-time during photodynamic therapy.
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Affiliation(s)
- A Rollan
- School of Applied Biological and Chemical Sciences, University of Ulster, Coleraine, UK
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25
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Flynn G, Hackett TJ, McHale L, McHale AP. Encapsulation of the thrombolytic enzyme, brinase, in photosensitized erythrocytes: a novel thrombolytic system based on photodynamic activation. J Photochem Photobiol B 1994; 26:193-6. [PMID: 7815192 DOI: 10.1016/1011-1344(94)07037-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
In order to circumvent many of the problems associated with the systemic administration of agents used in thrombolytic therapy, it was decided to investigate the possibility of using erythrocytes as carriers and delivery vehicles for these agents. The enzyme brinase, a fibrinolytic enzyme produced by Aspergillus oryzae, was loaded into rabbit erythrocytes using electroporation. The loading index for this enzyme was found to be 60% and incorporation appeared to be relatively stable over a period of 4 h. In order to facilitate the predetermined release of the loaded component from the erythrocytes, they were photosensitized using haematoporphyrin derivative (HPD) and release was demonstrated within 5 min of photoactivation. Inclusion of the loaded, photosensitized system into clotting blood and subsequent exposure to light demonstrated almost complete lysis of the clot. We believe that this system exhibits potential for use in thrombolytic therapy.
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Affiliation(s)
- G Flynn
- Biotechnology Group, School of Applied Biological and Chemical Sciences, University of Ulster, Coleraine, Co. Londonderry, UK
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26
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Abstract
The effect of formulation on cimetidine delivery to the pilosebaceous unit and other skin phases was studied. In vitro and in vivo deposition determinations as well as a pharmacodynamic antiandrogenic sebaceous gland bioassays were made. A complex variety of factors influence how the formulation affects both the degree of drug deposition and its pharmacological activity in the pilosebaceous unit. When cimetidine was applied in formulations at pH values where it was predominately unionized, the thermodynamic driving force proved the dominant factor in influencing the extent of drug deposition into the pilosebaceous unit. Although more cimetidine was deposited into the pilosebaceous unit in vivo from the phospholipid-based liposomal formulation when cimetidine was ionized, this formulation was also the only one devoid of significant antiandrogenic action. Of great importance, it is clear from the studies that deposition from complex formulations, such as liposomes, where bilayer/drug interactions can persist in the skin, may give a false impression of the activity of a drug within a tissue. Moreover, data for cimetidine in 50% alcohol solution show that one can maintain local effects while reducing systemic activity by simply manipulating drug concentration in the application.
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Affiliation(s)
- L M Lieb
- College of Pharmacy, University of Michigan, Ann Arbor 48109-1065
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27
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Abstract
Minoxidil, a potent antihypertensive, is moderately effective in the treatment of hair loss when it is applied to the scalp as a 2% solution in 60% ethanol, 20% propylene glycol and 20% water. Important questions remain concerning both the mechanism of delivery and the pathway of penetration of this drug from its ternary solvent system. Since preliminary studies in our laboratory indicated that water in the formulation influenced permeation far less than the other two solvents, we examined the relative deposition and penetration influences of binary combinations of ethanol and propylene glycol. When 50 microL/cm2 of the formulations was spread over hairless mouse skin sections mounted in Franz diffusion cells, only small amounts of minoxidil were actually recovered from the receiver compartments. Nevertheless, more minoxidil penetrated the skin as the proportion of ethanol in the mixtures was increased. To determine if these in vitro results formed a representative picture of the in vivo behaviors of these vehicles, selected deposition experiments were performed on live, anesthetized mice under experimental conditions similar to those used in the diffusion cell work. The good agreement between in vivo and in vitro studies may be a result of the relatively fast partitioning of the drug into the skin as compared to its diffusion through the skin.
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Affiliation(s)
- S Tata
- College of Pharmacy, University of Michigan, Ann Arbor 48109-1065
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28
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Abstract
With a view towards the design of a system incorporating both the use of chemotherapeutics and photodynamic therapy for use in cancer treatment modalities, erythrocytes have been loaded with methotrexate and subsequently photosensitized by exposure to hematoporphyrin derivative. Loading of methotrexate into erythrocytes has been optimized by examining variations in electroporation conditions. Maximum loading indices observed were in the region of 64%. In order to obtain rapid pre-defined release of chemotherapeutic from the system, the erythrocytes were photosensitized. Light-dependent release of methotrexate from the system was examined. In addition, studies measuring the cytotoxic effects of light-activated release from the system using Hela cells as a target, suggested that decreases in cell viability following exposure to light resulted from the combined effects of chemotherapy and photoradiation therapy. Potential applications and advantages associated with this novel system are discussed.
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Affiliation(s)
- G Flynn
- Department of Applied Biological and Chemical Sciences, University of Ulster, Coleraine, Co. Londonderry, Northern Ireland, UK
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29
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Abstract
The ability of a magnetically responsive material to function as a carrier for photosensitizing agents for use in photoradiation therapy (PRT) has been examined in vitro. The photosensitizer has been attached to the magnetically responsive matrix (Dynabeads) by non-specific adsorption, Intralipid-mediated adsorption and poly-L-lysine mediated adsorption. In these studies, it has been demonstrated that conditions of attachment of photosensitizer to the matrix may be adapted in order to facilitate a diffuse or highly localized photo-toxic effect on target cells in vitro. The authors believe that this system may represent a novel approach to targeting photosensitizing agents to specific areas, thereby circumventing some of the problems associated with conventional photoradiation therapy (PRT), particularly in hollow organs.
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Affiliation(s)
- G Flynn
- Department of Biological and Biomedical Sciences, University of Ulster, Coleraine, Co. Londonderry, Northern Ireland, UK
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30
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Nissim A, Hoogenboom HR, Tomlinson IM, Flynn G, Midgley C, Lane D, Winter G. Antibody fragments from a ‘single pot’ phage display library as immunochemical reagents. EMBO J 1994; 13:692-8. [PMID: 7508862 PMCID: PMC394860 DOI: 10.1002/j.1460-2075.1994.tb06308.x] [Citation(s) in RCA: 389] [Impact Index Per Article: 13.0] [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: 11/10/2022] Open
Abstract
The display of repertoires of antibody fragments on the surface of filamentous bacteriophage offers a new way of making antibodies with predefined binding specificities. Here we explored the use of this technology to make immunochemical reagents to a range of antigens by selection from a repertoire of > 10(8) clones made in vitro from human V gene segments. From the same 'single pot' repertoire, phage were isolated with binding activities to each of 18 antigens, including the intracellular proteins p53, elongation factor EF-1 alpha, immunoglobulin binding protein, rhombotin-2 oncogene protein and sex determining region Y protein. Both phage and scFv fragments secreted from infected bacteria were used as monoclonal and polyclonal reagents in Western blots. Furthermore the monoclonal reagents were used for epitope mapping (a new epitope of p53 was identified) and for staining of cells. This shows that antibody reagents for research can be readily derived from 'single pot' phage display libraries.
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Affiliation(s)
- A Nissim
- MRC Centre for Protein Engineering, Cambridge, UK
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31
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Bunni L, Hackett TJ, McHale L, Flynn G, McHale AP. Molecular cloning and functional expression of a Talaromyces emersonii derived alpha-amylase encoding genetic determinant in a human cell line. Biotechnol Lett 1993. [DOI: 10.1007/bf00131196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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32
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Hirst MC, Barnicoat A, Flynn G, Wang Q, Daker M, Buckle VJ, Davies KE, Bobrow M. The identification of a third fragile site, FRAXF, in Xq27--q28 distal to both FRAXA and FRAXE. Hum Mol Genet 1993; 2:197-200. [PMID: 8499907 DOI: 10.1093/hmg/2.2.197] [Citation(s) in RCA: 45] [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: 01/31/2023] Open
Abstract
FRAXA is unique amongst fragile sites in that it is intimately involved with a specific clinical phenotype, the fragile X syndrome. Whilst the majority of fragile X individuals have been found to have a characteristic mutation in the FMR1 gene, a small proportion of individuals exhibiting fragility have no such mutation. Investigation of the site of chromosome fragility in these FMR1 mutation negative, fragile X site positive individuals, has identified a second site of fragility, FRAXE. However, the presence of FRAXE has not explained all such cases. Here we describe a fragile X site positive, FMR1 mutation negative family, in which chromosome fragility is not due to the FRAXA or FRAXE but is due to a third site designated FRAXF. Using fluorescent in situ hybridisation (FISH) this site is shown to lie over 1Mb distal to FRAXA. The identification of a third fragile site in this small region of the X chromosome provides an opportunity to extend our studies of the molecular nature of chromosome fragility.
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Affiliation(s)
- M C Hirst
- Molecular Genetics Group, Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, UK
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33
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Almond MK, Smith A, Cohen RD, Iles RA, Flynn G. Substrate and pH effects on glutamine synthesis in rat liver. Consequences for acid-base regulation. Biochem J 1991; 278 ( Pt 3):709-14. [PMID: 1898360 PMCID: PMC1151404 DOI: 10.1042/bj2780709] [Citation(s) in RCA: 11] [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] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Switching in acidosis of hepatic nitrogen disposal from urea synthesis to NH4+ and net glutamine production was demonstrated in the isolated perfused livers of starved male Wistar rats. Lactate was preferred to glucose as the substrate for the carbon skeleton of glutamine synthesized over the pH range 6.9-7.5. This is necessary if the switch away from a proton-producing process (ureagenesis) in acidosis is to constitute an acid-base regulating system intrinsic to the liver. Glutamine balance shifted with pH from marked net uptake to small net output under acidotic conditions (pH 7.5-6.9), an effect due solely to a decrease in glutamine uptake. NH4+ uptake by the liver had a linear relationship with pH, being markedly decreased in acidosis because glutamine synthesis was insufficient to compensate for the decreased incorporation into urea. Animals rendered chronically acidotic showed a lower central venous plasma urea concentration and a raised NH4+ concentration, but their livers synthesized no more glutamine when perfused at an acidotic pH than did normal livers. We conclude that perivenous hepatocytes may not be efficient scavengers of NH4+ ions, which must be partly disposed of elsewhere by non-proton-generating pathways if inhibition of ureagenesis is to represent a hepatic acid-base regulating system.
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Affiliation(s)
- M K Almond
- Medical Unit, London Hospital Medical College, University of London, U.K
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34
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Hirst MC, Rack K, Nakahori Y, Roche A, Bell MV, Flynn G, Christadoulou Z, MacKinnon RN, Francis M, Littler AJ. A YAC contig across the fragile X site defines the region of fragility. Nucleic Acids Res 1991; 19:3283-8. [PMID: 2062644 PMCID: PMC328323 DOI: 10.1093/nar/19.12.3283] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [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: 12/30/2022] Open
Abstract
The fragile X syndrome is a common cause of mental retardation and is associated with a fragile site at Xq27.3 (FRAXA). Recently, evidence has been presented for the role of methylation and genomic imprinting in the expression of the disease. We have identified a site of methylation in patients by long range restriction mapping of the region. In this paper we present a YAC contig of this area, localise the CpG sequences which are methylated, and show by in situ hybridisation that the site of fragility lies within this region.
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Affiliation(s)
- M C Hirst
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
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35
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Abstract
Stainless-steel templates of various thicknesses (75, 200, 800, and 1600 microns) were used to apply propylene glycol/water gels containing methyl or propyl p-aminobenzoates to silicone rubber membranes, and drug delivery was studied with the use of the Bronaugh diffusion cell under conditions in which the drug was initially in thermodynamic equilibrium with respect to the application and membrane. Theoretical diffusion profiles were generated with the use of a model which assumes that diffusional gradients exist within the application. To use the model equation, previously derived for the initial condition in which the drug is in thermodynamic equilibrium with respect to the application and membrane, drug diffusivity in both the application and the membrane and the drug's membrane/vehicle partition coefficient were independently determined. In general, agreement between experimental and theoretical results was within 25%.
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Affiliation(s)
- W Addicks
- College of Pharmacy, University of Michigan, Ann Arbor 48109
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36
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Joly JC, Flynn G, Purich DL. The microtubule-binding fragment of microtubule-associated protein-2: location of the protease-accessible site and identification of an assembly-promoting peptide. J Biophys Biochem Cytol 1989; 109:2289-94. [PMID: 2808529 PMCID: PMC2115882 DOI: 10.1083/jcb.109.5.2289] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Thrombin cleavage of bovine brain microtubule-associated protein (MAP-2) yields two stable limit polypeptide fragments (28,000 and 240,000 Mr). The smaller cleavage product contains the microtubule-binding domain and is derived from the carboxyl terminus of MAP-2 while the 240,000 Mr fragment is derived from the amino terminus. The amino terminal sequence of the smaller cleavage product is homologous with the microtubule-binding fragment of tau in sequence and in a similar location relative to three imperfect octadecapeptide repeats implicated in microtubule binding. Peptides corresponding to the cleavage site and the three repeats of MAP-2 were synthesized. Only the second octadecapeptide repeat (VTSKCGSLKNIRHRPGGG) was capable of stimulating microtubule nucleation and elongation. Microtubules formed in the presence of this peptide displayed normal morphology and retained the inhibition properties of calcium ion, podophyllotoxin, and colchicine. Our result indicates that a region comprising only approximately 1% of the MAP-2 sequence can promote microtubule assembly.
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Affiliation(s)
- J C Joly
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville 32610
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37
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Weiner N, Williams N, Birch G, Ramachandran C, Shipman C, Flynn G. Topical delivery of liposomally encapsulated interferon evaluated in a cutaneous herpes guinea pig model. Antimicrob Agents Chemother 1989; 33:1217-21. [PMID: 2802550 PMCID: PMC172628 DOI: 10.1128/aac.33.8.1217] [Citation(s) in RCA: 97] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The topical delivery of liposomally encapsulated interferon was evaluated in the cutaneous herpes simplex virus guinea pig model. Application of liposomally entrapped interferon caused a reduction of lesion scores, whereas application of interferon formulated as a solution or as an emulsion was ineffective. The method of liposomal preparation rather than the lipid composition of the bilayers appeared to be the most important factor for reducing lesion scores. Only liposomes prepared by the dehydration-rehydration method were effective. This finding implied that the dehydration and subsequent rehydration of the liposomes facilitate partitioning of the interferon into liposomal bilayers, where the drug is positioned for transfer into the lipid compartment of the stratum corneum. Liposomes do not appear to function as permeation enhancers but seem to provide the needed physicochemical environment for transfer of interferon into the skin.
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Affiliation(s)
- N Weiner
- College of Pharmacy, University of Michigan, Ann Arbor 48109
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38
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Flynn G, Wilson JA, Currie CT, Philip M. Medical problems and care needs of elderly patients in a mental handicap hospital. Health Bull (Edinb) 1988; 46:173-5. [PMID: 3182258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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39
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Wilson JA, Flynn G, Smith RG. Communication of drug treatment to general practitioners. Br Med J (Clin Res Ed) 1988; 296:211-2. [PMID: 3123001 PMCID: PMC2544936 DOI: 10.1136/bmj.296.6616.211-c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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40
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Flynn G, Purich DL. GTP regeneration influences interactions of microtubules, neurofilaments, and microtubule-associated proteins in vitro. J Biol Chem 1987; 262:15443-7. [PMID: 3680206] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Interactions of microtubules, neurofilaments, and microtubule-associated proteins were investigated by turbidity and falling-ball viscometry measurements. We found evidence of endogenous GTPase activity in neurofilaments and microtubule-associated proteins (MAPs) in preparations that do not include urea or heat treatment, respectively. The absence or presence of either adenyl-5'-yl imidodiphosphonic acid or a GTP-regenerating system markedly influenced observed polymerization and gelation characteristics. Most significantly, the apparent viscosity of neurofilament and microtubule samples did not display a biphasic optimal MAP concentration profile when a GTP-regenerating system was operant. Likewise, GTP regeneration promoted the recovery of gelation following mechanical disruption of neurofilament/MAP/microtubule mixtures. These and other observations require some reassessment of proposed roles for microtubule-associated proteins in modulating neurofilament-microtubule interactions in vitro.
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Affiliation(s)
- G Flynn
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville 32610
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41
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Flynn G, Joly JC, Purich DL. The 28,000 Mr microtubule-binding domain of microtubule-associated protein-2 also contains a neurofilament-binding site. Biochem Biophys Res Commun 1987; 148:1453-9. [PMID: 3120718 DOI: 10.1016/s0006-291x(87)80295-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We have developed a thrombin proteolytic cleavage procedure to obtain higher yields of the Mr 28,000 microtubule-binding and Mr 240,000 microtubule-projection components of MAP-2. The former is a highly basic component, whereas the latter and intact MAP-2 are acidic polypeptides. Most notably, our studies reveal that this Mr 28,000 fragment binds to neurofilaments, but the Mr 240,000 projection domain fails to interact. These data indicate that microtubules and neurofilaments share a common binding site on high-molecular-weight MAP-2.
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Affiliation(s)
- G Flynn
- Department of Biochemistry and Molecular Biology, University of Florida College of Medicine, Gainesville 32610
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42
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43
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Abstract
There exists some uncertainty about the hazards which the quenching of a superconducting magnet would present to a subject undergoing an NMR examination. To investigate this problem, a 1.6-T whole-body magnet was quenched with an anesthetized pig lying in the bore. This paper reports our findings which, in the circumstances of this experiment, suggest that the risks are small.
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44
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Flynn G, Heard L, Thomas J. Admitting by computer. Hosp Adm Can 1978; 20:32-4. [PMID: 10308200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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45
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