51
|
Koschella A, Inngjerdingen K, Paulsen BS, Morris GA, Harding SE, Heinze T. Unconventional Methyl Galactan Synthesized via the Thexyldimethylsilyl Intermediate: Preparation, Characterization, and Properties. Macromol Biosci 2008; 8:96-105. [PMID: 17902190 DOI: 10.1002/mabi.200700120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Reaction of a beta-(1 --> 4) linked galactan with TDMS chloride followed by methylation and desilylation yields methyl galactans with unconventional functionalization patterns. The products were characterized via FTIR and NMR of the intact polymer and by CE after controlled depolymerization. A TDMS-derivatized methyl galactan contains differently methylated secondary hydroxyl groups. SEC and analytical ultracentrifugation showed a consistent decrease in the molecular weight after the consecutive reaction steps. Biological studies revealed that the methyl galactans are less active in complement fixation assays as compared with a 3-O-methyl galactan-enriched polysaccharide fraction isolated from Acanthus ebracteatus.
Collapse
|
52
|
Morris GA, Ang S, Hill SE, Lewis S, Schäfer B, Nobbmann U, Harding SE. Molar mass and solution conformation of branched α(1→4), α(1→6) Glucans. Part I: Glycogens in water. Carbohydr Polym 2008. [DOI: 10.1016/j.carbpol.2007.05.029] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
53
|
Inngjerdingen KT, Patel TR, Chen X, Kenne L, Allen S, Morris GA, Harding SE, Matsumoto T, Diallo D, Yamada H, Michaelsen TE, Inngjerdingen M, Paulsen BS. Immunological and Structural Properties of a Pectic Polymer from Glinus Oppositifolius. Glycobiology 2007; 17:1299-310. [PMID: 17726087 DOI: 10.1093/glycob/cwm088] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The aim of this paper was to further elucidate the structure and the immunomodulating properties of the pectic polymer GOA2, previously isolated from Glinus oppositifolius. Enzymatic treatment of GOA2 by endo-alpha-d-(1 --> 4)-polygalacturonase led to the isolation of three pectic subunits, GOA2-I, GOA2-II, and GOA2-III, in addition to oligogalacturonides. GOA2-I was shown to consist of 1,2-linked Rhap and 1,4-linked GalpA in an approximately 1:1 ratio, and NMR-analysis showed that the monomers were linked together in a strictly alternating manner. The galactose units in GOA2-I were found as terminal-, 1,3-, 1,6-, 1,4-, 1,3,4-, and 1,3,6-linked residues, while the arabinofuranosyl existed mainly as terminal- and 1,5-linked units. A rhamnogalacturonan-I type structure was suggested being the predominant part of GOA2-I. According to linkage analysis GOA2-II and GOA2-III contained glycosidic linkages characteristic for rhamnogalacturonan-II type structures. GOA2 was shown by sedimentation velocity in the analytical ultracentrifuge, to have a broad degree of polydispersity with a mode s(20,w) value of approximately 1.9 S, results reinforced by atomic force microscopy measurements. The polydispersity, as manifested by the proportion of material with s(20,w) > 3 S, decreased significantly with enzyme treatment. The abilities of GOA2, GOA2-I, GOA2-II, and GOA2-III to induce the proliferation of B cells, and to exhibit complement fixing activities were tested. In both test systems, GOA2-I showed significantly greater effects compared to its native pectin GOA2. GOA2-I was in addition shown to exhibit a more potent intestinal immune stimulating activity compared to GOA2. The ability of GOA2 to induce secretion of proinflammatory cytokines was examined. Marked upregulations in mRNA for IL-1beta from rat macrophages and IFN-gamma from NK cells were found.
Collapse
|
54
|
Patel TR, Harding SE, Ebringerova A, Deszczynski M, Hromadkova Z, Togola A, Paulsen BS, Morris GA, Rowe AJ. Weak self-association in a carbohydrate system. Biophys J 2007; 93:741-9. [PMID: 17483161 PMCID: PMC1913144 DOI: 10.1529/biophysj.106.100891] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2006] [Accepted: 03/14/2007] [Indexed: 11/18/2022] Open
Abstract
The physiological importance of weak interactions between biological macromolecules (molar dissociation constants >10 microM) is now well recognized, particularly with regard to cell adhesion and immunological phenomena, and many weak interactions have been measured for proteins. The concomitant importance of carbohydrate-carbohydrate interactions has also been identified, although no weak interaction between pure carbohydrate systems has ever been measured. We now demonstrate for the first time to our knowledge using a powerful probe for weak interactions--sedimentation velocity in the analytical ultracentrifuge--that at least some carbohydrates (from the class of polysaccharides known as heteroxylans and demonstrated here to be biologically active) can show well-defined weak self-interactions of the "monomer-dimer" type frequently found in protein systems. The weak interaction between the heteroxylans is shown from a temperature dependence study to be likely to be hydrophobic in nature.
Collapse
|
55
|
Morris GA, Sims IM, Robertson AJ, Furneaux RH. Investigation into the physical and chemical properties of sodium caseinate-maltodextrin glyco-conjugates. Food Hydrocoll 2004. [DOI: 10.1016/j.foodhyd.2004.04.013] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
56
|
Petalidis L, Bhattacharyya S, Morris GA, Collins VP, Freeman TC, Lyons PA. Global amplification of mRNA by template-switching PCR: linearity and application to microarray analysis. Nucleic Acids Res 2003; 31:e142. [PMID: 14602935 PMCID: PMC275579 DOI: 10.1093/nar/gng142] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2003] [Revised: 08/22/2003] [Accepted: 09/24/2003] [Indexed: 11/14/2022] Open
Abstract
Conventional approaches to target labelling for expression microarray analysis typically require relatively large amounts of total RNA, a serious limitation when the sample available is small. Here we explore the cycle-dependent amplification characteristics of Template-Switching PCR and validate its use for microarray target labelling. TS-PCR identifies up to 80% of the differentially expressed genes identified by direct labelling using 30-fold less input RNA for the amplification, with the equivalent of 1000-fold less starting material being used for each hybridisation. Moreover, the sensitivity of microarray experiments is increased considerably, allowing the identification of differentially expressed transcripts below the level of detection using targets prepared by direct labelling. We have also validated the fidelity of amplification and show that the amplified material faithfully represents the starting mRNA population. This method outperforms conventional labelling strategies, not only in terms of sensitivity and the identification of differentially expressed genes, but it is also faster and less labour intensive than other amplification protocols.
Collapse
|
57
|
|
58
|
Morris GA, Hromádková Z, Ebringerová A, Malovı́ková A, Alföldi J, Harding SE. Modification of pectin with UV-absorbing substitutents and its effect on the structural and hydrodynamic properties of the water-soluble derivatives. Carbohydr Polym 2002. [DOI: 10.1016/s0144-8617(01)00268-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
59
|
Morris GA, Foster TJ, Harding SE. Further observations on the size, shape, and hydration of casein micelles from novel analytical ultracentrifuge and capillary viscometry approaches. Biomacromolecules 2002; 1:764-7. [PMID: 11710209 DOI: 10.1021/bm0055807] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The size, shape, and hydration of casein micelles were estimated using a combination of sedimentation velocity (time-derivative analysis) in the analytical ultracentrifuge and capillary viscometry applied to skimmed milk. On the basis of sedimentation time-derivative and Wales-van Holde analyses the casein micelles appear as large spherical molecules of s0T,b = 845S, Mw approximately 2.8 x 10(8), hydrodynamic radius approximately 77.8 nm, and ks/[eta] = 1.6. The molecular hydration (i.e., the extent of chemically bound and physically entrained solvent) was calculated to be 3.4 g/g. These results appear to be in good agreement with comparable results from electron microscopy and dynamic light scattering.
Collapse
|
60
|
Harris RK, Kinnear KA, Morris GA, Stchedroff MJ, Samadi-Maybodi A, Azizi N. Silicon-29 diffusion-ordered NMR spectroscopy (DOSY) as a tool for studying aqueous silicates. Chem Commun (Camb) 2001:2422-3. [PMID: 12239996 DOI: 10.1039/b108325m] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The first use of silicon-29 diffusion-ordered NMR spectroscopy (DOSY) is reported, in a study of the speciation of aqueous silicates.
Collapse
|
61
|
Loening NM, Keeler J, Morris GA. One-dimensional DOSY. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2001; 153:103-112. [PMID: 11700086 DOI: 10.1006/jmre.2001.2423] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new NMR experiment for correlating diffusion coefficients and chemical shifts is presented. This experiment provides the same information as the conventional DOSY experiment, but only requires a single dimension because a nonuniform magnetic field gradient is used to encode the diffusion information into the lineshapes of the peaks in the chemical shift dimension. By fitting the resulting lineshapes, the diffusion coefficient for each peak in the spectrum can be extracted. Using this experiment, a qualitative DOSY spectrum can be generated using the results from a single one-dimensional experiment. Quantitative results can be determined with the use of reference experiments.
Collapse
|
62
|
Bowyer PJ, Swanson AG, Morris GA. Analyzing and correcting spectrometer temperature sensitivity. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2001; 152:234-246. [PMID: 11567577 DOI: 10.1006/jmre.2001.2404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Stability and reproducibility of the spectrometer are fundamental to the success of many modern NMR experiments. Variation in room temperature is a particularly important source of instability, in part because it can cause coherent artifacts in NMR spectra. Small changes in room temperature lead to corresponding changes in the phases, amplitudes, and frequencies of NMR signals. These can lead in turn to apparently random spectral artifacts such as t(1)-noise in two-dimensional (2D) NMR and to the incomplete cancellation of signals in difference spectra, but also, importantly, to F(1) satellite signals in 2D spectra. These "parallel diagonals" arise from the use of air conditioning, which typically forces room temperature to oscillate within a fixed band. Work to identify, quantify, and suppress sources of temperature sensitivity in a modern 300-MHz spectrometer has led to a greater than 10-fold improvement in the signal-to-artifact ratio.
Collapse
|
63
|
Stewart LJ, Bailey S, Collison D, Morris GA, Preece I, Garner CD. In vivo oxo transfer: reactions of native and W-substituted dimethyl sulfoxide reductase monitored by (1)H NMR spectroscopy. Chembiochem 2001; 2:703-6. [PMID: 11828507 DOI: 10.1002/1439-7633(20010903)2:9<703::aid-cbic703>3.0.co;2-v] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
64
|
Morris GA, Zhou H, Stern CL, Nguyen ST. A general high-yield route to bis(salicylaldimine) zinc(II) complexes: application to the synthesis of pyridine-modified salen-type zinc(II) complexes. Inorg Chem 2001; 40:3222-7. [PMID: 11399196 DOI: 10.1021/ic010090o] [Citation(s) in RCA: 137] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A general, direct, and high-yield synthesis of bis(salicylaldimine) zinc complexes from the ligands and Et(2)Zn is reported. This synthetic method is particularly valuable, not only because it allows the efficient preparation of salen-type complexes of zinc but also because it can be used to prepare bifunctional pyridine-modified zinc(II) bis(salicylidene) complexes, which are potentially useful compounds for applications in asymmetric catalysis and materials chemistry. The synthesis and complete structural characterization of a new series of pyridine-modified zinc(II) bis(salicylidene) ligands is discussed.
Collapse
|
65
|
Frau S, Bichenkova EV, Morris GA, Douglas KT. Binding of a porphyrin conjugate of Hoechst 33258 to DNA. II. NMR spectroscopic studies detect multiple binding modes to a 12-mer nonself-complementary duplex DNA. NUCLEOSIDES, NUCLEOTIDES & NUCLEIC ACIDS 2001; 20:145-56. [PMID: 11303560 DOI: 10.1081/ncn-100001443] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
We have probed by 1H NMR spectroscopy the molecular basis of the interaction between Hoechst 33258 conjugated to a des-metalloporphyrin and a non self-complementary duplex DNA sequence, designed on the known chemical nuclease selectivity of this system. The imino NMR spectra are consistent with two distinct families of structure, that is, PORHOE binding either way along the duplex. 2D spectral, T2, and linewidth data suggest multiple species within the two conformational families.
Collapse
|
66
|
Mordi MN, Pelta MD, Boote V, Morris GA, Barber J. Acid-catalyzed degradation of clarithromycin and erythromycin B: a comparative study using NMR spectroscopy. J Med Chem 2000; 43:467-74. [PMID: 10669574 DOI: 10.1021/jm9904811] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
One of the major drawbacks in the use of the antibiotic erythromycin A is its extreme acid sensitivity, leading to degradation in the stomach following oral administration. The modern derivative clarithromycin degrades by a different mechanism and much more slowly. We have studied the pathway and kinetics of the acid-catalyzed degradation of clarithromycin and of erythromycin B, a biosynthetic precursor of erythromycin A which also has good antibacterial activity, using (1)H NMR spectroscopy. Both drugs degrade by loss of the cladinose sugar ring and with similar rates of reaction. These results suggest that erythromycin B has potential as an independent therapeutic entity, with superior acid stability compared with erythromycin A and with the advantage over clarithromycin of being a natural product.
Collapse
|
67
|
Bowyer PJ, Swanson AG, Morris GA. Randomized acquisition for the suppression of systematic F1 artifacts in two-dimensional NMR spectroscopy. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1999; 140:513-515. [PMID: 10497061 DOI: 10.1006/jmre.1999.1882] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
2D spectra, particularly for homonuclear correlation, can show a variety of artifactual signals in the F1 domain. Common sources include carry-over of signal modulation from one transient to the next ("rapid pulsing artifacts") and systematic variations in room temperature ("parallel diagonals"). In both cases there is one very simple expedient which can greatly reduce the impact of these sources of error. Multidimensional data sets are almost invariably recorded by simply incrementing or decrementing evolution periods, largely for reasons of convenience and historical precedent. If instead the sampling of the evolution periods is carried out in random order, the perturbations responsible for the sharp F1 signals in the conventional experiment manifest themselves as t1 noise. Since the randomized acquisition redistributes coherent artifactual signals randomly in F1, the maximum artifactual signal is substantially reduced in the randomized experiment and no longer appears in the form of misleading distinct peaks.
Collapse
|
68
|
Bichenkova EV, Marks D, Dobrikov MI, Vlassov VV, Morris GA, Douglas KT. Refined high-field NMR solution structure of a binary-addressed pyrene/perfluoro-azide complementary DNA oligonucleotide system shows extensive distortion in the central nick region. J Biomol Struct Dyn 1999; 17:193-211. [PMID: 10563570 DOI: 10.1080/07391102.1999.10508353] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
The structural analysis of the photoactivated binary system of complementary-addressing nucleic acid sequences (1:2:3) by high-resolution NMR spectroscopy and restrained molecular dynamics is reported. The binary system comprised a 12 base-pair target DNA sequence, pdGTATCAGTTTCT (1), and two hexanucleotides, (dAGAAACp-L-Az (2) and Pyr-pdTGATAC (3)), complementary to neighbouring sites in the target DNA. Oligonucleotide (2) is conjugated with a p-azidotetrafludrobenzyl group (Az) via a linker group (L), and the other oligonucleotide (3) is equipped with the photosensitizing pyrenyl-1-methylamino group (Pyr). We now extend the structural analysis of 1:2:3, which was previously based on qualitative 2D 1H-NMR data and thermodynamic analysis of complex formation from UV-visible thermal denaturation experiments. In the current work structural refinement was performed by separate molecular dynamics runs for six different starting structures based on 318 proton-proton distance-range constraints, evaluated from the 1H-NOESY spectrum (tau(mix) = 200 ms, 600 MHz) using complete relaxation matrix analysis (NMR/TRIAD/MARDIGRAS). Additional Watson-Crick hydrogen bond restraints were included in the calculations based on the detected signals from the exchangeable protons, using REFOPT(NY) methods. The final averaged structure obtained from the six refined co-ordinate sets showed a considerable degree of axis bend (62.5 degrees) with the bending point in the middle of the duplex in the region of the backbone nick between the two short oligonucleotides. The complex behaves dynamically as the equivalent of two short B-DNA-like duplexes displaying a hinge-like flexing at their junction. In all final structures the Pyr function location was very restricted, the aromatic group lying in the duplex minor groove near residues 4T, 5C and 2T. In contrast, the location of the perfluoroazido group was different in all the final structures, indicating the high flexibility of this group in the duplex. The only feature common to all six final azido group orientations was the outside location on the side of the major groove. The distance between the Pyr and Az groups varied from 11 A to 24 A for the six final structures (17 A, final average structure). The dynamics of duplex denaturation for 1:2:3 was probed by monitoring the temperature-induced NMR line broadening of the imino protons in a 1D variable temperature NMR experiment. The melting of 1:2:3 starts both from the ends and from the middle part of the duplex at the backbone break between the two short oligonucleotides reflecting the destabilisation of the pyrene-arylazido nick region in the duplex.
Collapse
|
69
|
Morris GA, Lehman GA. Maxillary canine restoration: a case report. COMPENDIUM OF CONTINUING EDUCATION IN DENTISTRY (JAMESBURG, N.J. : 1995) 1999; 20:823-6, 828, 830 passim; quiz 834. [PMID: 10649953] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
The replacement of a single tooth with osseointegrated dental implants presents a unique challenge to both the prosthodontist and the surgeon. When anterior teeth are replaced, it is difficult to design an occlusal scheme that will direct forces down the long axis of an implant. This is especially true when the canine is involved. Wide-diameter implants offer advantages, such as increased surface area of implant to bone, stronger prosthetics, stronger implants, and less screw loosening or breakage when compared to standard-diameter implants. The single-stage technique is advantageous in terms of soft-tissue predictability, and it eliminates the need for second-stage surgery.
Collapse
|
70
|
Werbelow LG, Morris GA, Kumar P, Kowalewski J. Cross-correlated quadrupolar spin relaxation and carbon-13 lineshapes in the (13)CD(2) spin grouping. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1999; 140:1-8. [PMID: 10479544 DOI: 10.1006/jmre.1999.1792] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Lineshape calculations are reported for a spin system consisting of a spin-12 nucleus scalar-coupled to two magnetically equivalent spin-1 nuclei, e.g., a CD(2) group. It is found that, because of the differential line broadening, the peak height ratio of the five spin-12 nucleus transitions is expected to deviate from the integrated intensity ratio of 1:2:3:2:1. The deviation is dependent on the extent of cross-correlation between the two quadrupolar interactions. The theoretical predictions for peak height ratios and for bandshapes are tested for the carbon-13 spectrum of perdeuterated ethylene glycol, and iterative fitting is used to obtain an estimate of the extent of the correlation between the quadrupolar interactions for the two deuterons.
Collapse
|
71
|
Chilvers PB, Morris GA. Automated shimming with normal spectrometer hardware: 3D profile edge shimming. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1998; 133:210-215. [PMID: 9654490 DOI: 10.1006/jmre.1998.1464] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A novel method is proposed for automated magnetic field homogeneity adjustment in high-resolution NMR. The method uses measurements of the edge frequencies of slice profiles recorded under static gradients to obtain three-dimensional magnetic field maps and does not require significant extra spectrometer hardware. Results are presented for the "cold" shimming of 5- and 10-mm-diameter probes in a 400-MHz narrow bore magnet. Copyright 1998 Academic Press.
Collapse
|
72
|
Barjat H, Morris GA, Swanson AG. A three-dimensional DOSY-HMQC experiment for the high-resolution analysis of complex mixtures. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1998; 131:131-138. [PMID: 9533915 DOI: 10.1006/jmre.1997.1332] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A three-dimensional experiment is described in which NMR signals are separated according to their proton chemical shift, 13C chemical shift, and diffusion coefficient. The sequence is built up from a stimulated echo sequence with bipolar field gradient pulses and a conventional decoupled HMQC sequence. Results are presented for a model mixture of quinine, camphene, and geraniol in deuteriomethanol. Copyright 1998 Academic Press.
Collapse
|
73
|
Agrawal PK, Bunsawansong P, Morris GA. Dependence of the 1H NMR chemical shifts of ring F resonances on the orientation of the 27-methyl group of spirostane-type steroidal sapogenins. PHYTOCHEMISTRY 1998; 47:255-257. [PMID: 9431674 DOI: 10.1016/s0031-9422(97)00481-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
A relationship between the 1H NMR chemical shifts of the ring F resonances and orientation of the H3-27 group has been derived for the establishment of 25R- and 25S-stereochemistry in spirostane type of steroidal sapogenins.
Collapse
|
74
|
Zhu XP, Chilvers PB, Hutchinson CE, Morris GA, Hawnaur JM, Adams JE, Taylor CJ. Contrast-modified gradient echo imaging using rotary echo preparatory pulses. MAGMA (NEW YORK, N.Y.) 1997; 5:193-200. [PMID: 9351023 DOI: 10.1007/bf02594582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The use of on-resonance 121 binomial composite pulses in two- or three-dimensional magnetization-prepared gradient-recalled echo magnetic resonance imaging experiments generates rotary echoes, leading to an increase in contrast range that is, in part, determined by the ratio of T2 to T1. In comparison with other fast gradient-recalled echo imaging techniques designed for enhanced T2 contrast, this method is more robust with respect to radiofrequency field inhomogeneity and less sensitive with respect to motion artifacts. Three-dimensional parametric images may be calculated using least-squares fitting based on a simple model for steady-state longitudinal magnetization during the imaging sequences.
Collapse
|
75
|
Barjat H, Chilvers PB, Fetler BK, Horne TJ, Morris GA. A Practical Method for Automated Shimming with Normal Spectrometer Hardware. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1997; 125:197-201. [PMID: 9245381 DOI: 10.1006/jmre.1996.1094] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
|
76
|
Jones RP, Morris GA, Waterton JC. The spatial dependence of spin-echo signals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1997; 124:291-297. [PMID: 9169218 DOI: 10.1006/jmre.1996.1014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The signals in NMR spin echoes which are refocused by 90 degrees pulses are spatially modulated. The spatial modulation is not normally observed in images or profiles obtained using Hahn or stimulated echoes, but may cause errors if the sample structure varies on the distance scale of the modulation. Localized spectra measured using stimulated echoes will also show errors under these conditions. Simple Fourier-transform arguments show that conditions which allow the modulation to become visible in an image or profile have the effect of introducing a second echo into the time-domain acquisition window. Phase cycling may be used to remove the spatial dependence of the signals.
Collapse
|
77
|
Zhu XP, Hutchinson CE, Chilvers PB, Morris GA, Hawnaur JM, Taylor CJ. Off-resonance binomial composite pulses in 2D and 3D fat/water imaging at 0.5 T. Br J Radiol 1995; 68:134-40. [PMID: 7735743 DOI: 10.1259/0007-1285-68-806-134] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
A new method of acquiring two-dimensional (2D) and three-dimensional (3D) fat/water decomposed images on a 0.5 T magnetic resonance (MR) imaging system is described. The method uses a gradient-recalled echo (GRE) sequence incorporating a composite 121 pulse, originally used for magnetization transfer contrast (MTC) experiments, for frequency-selective pre-saturation. By applying the 121 pulse off resonance, a sharp discrimination between the chemically shifted water and fat signals may be obtained using a composite pulse as short as 4 ms. Phantom studies demonstrate that suppression ratios as high as 50:1 are achievable. The new method has been applied to volunteers and patients, and good fat/water images of limb, abdomen, head and neck obtained. The new method can be incorporated into other pulse sequences related to GRE, such as phase contrast (PC) and time-of-flight (TOF), and represents the first practical (i.e. rapid) method for 3D fat/water imaging at an operating field as low as 0.5 T.
Collapse
|
78
|
Morris GA, Freemont AJ. Direct observation of the magnetization exchange dynamics responsible for magnetization transfer contrast in human cartilage in vitro. Magn Reson Med 1992; 28:97-104. [PMID: 1435226 DOI: 10.1002/mrm.1910280110] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Saturating irradiation far off-resonance can lead to diminution in the water signal seen in MRI, giving rise to magnetization transfer contrast. This results from transfer of magnetization between "solid" protons with restricted motion, which give rise to a band some tens of kilohertz wide, and the narrow signal from mobile protons. In the work reported here a high-power pulse spectrometer, which can detect signals from both mobile and immobile protons, was used to investigate the dynamics of magnetization transfer in cartilage in vitro. Magnetization transfer in modified Hoffman-Forsén inversion transfer experiments was well-described by a single rate constant model; full analytical solutions are offered for the resultant biexponential magnetization recovery curves. The use of pulsed methods to generate magnetization contrast may in some circumstances offer advantages over the steady-state saturation methods used hitherto.
Collapse
|
79
|
Cole PR, Jasani MK, Wood B, Freemont AJ, Morris GA. High resolution, high field magnetic resonance imaging of joints: unexpected features in proton images of cartilage. Br J Radiol 1990; 63:907-9. [PMID: 2252990 DOI: 10.1259/0007-1285-63-755-907] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
|
80
|
Crawford JM, Krisko JM, Morris GA, Chambers DA. The distribution of Langerhans cells and CD1a antigen in healthy and diseased human gingiva. REGIONAL IMMUNOLOGY 1989; 2:91-7. [PMID: 2484334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The distribution of CD1a antigen in gingival epithelium of clinically healthy gingiva was examined and compared with the distribution in gingival epithelium of adult periodontitis lesions. Cryostat sections were examined with monoclonal antibodies to CD1a antigen using the ABC immunoperoxidase technique. In healthy gingiva, CD1a was limited to Langerhans cells (LC) which were observed throughout the length of the external epithelium and orosulcular epithelium. The numbers of LC expressed either per unit length of orosulcular epithelium or per mm2 were similar to the numbers in external gingiva. Junctional epithelium contained few if any dendritic LC. The numbers of LC in pocket epithelium of adult periodontitis lesions were significantly lower compared with orosulcular epithelium of healthy tissue and compared with external gingiva of diseased tissue (p less than 0.005). In many sections, no LC were identified in pocket epithelium. In 5 of 8 adult periodontitis sites, CD1a was also observed in association with the membranes of suprabasal keratinocytes in external and pocket epithelium in areas where no LC were identified. These findings provide further evidence that changes in gingival epithelial cells occur in periodontal disease which are analogous to those documented in dermatological diseases and suggest that epithelium may play a role in gingival homeostasis and in the pathogenesis of periodontal diseases.
Collapse
|
81
|
Clayden NJ, Inagaki F, Williams RJ, Morris GA, Tori K, Tokura K, Miyazawa T. Two-dimensional NMR spectroscopy of siomycin A. Proton--carbon-13 chemical shift correlation. EUROPEAN JOURNAL OF BIOCHEMISTRY 1982; 123:127-31. [PMID: 6279393 DOI: 10.1111/j.1432-1033.1982.tb06508.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
A trial application of a recent two-dimensional nuclear magnetic resonance experiment to the polypeptide antibiotic siomycin A is described. Proton--carbon-13 chemical shift correlation measures the proton and carbon-13 chemical shift for each directly bonded CH group in a molecule, in a single experiment. The resultant map of correlated chemical shifts enables the carbon-13 spectrum to be assigned directly from the known proton shifts, and allows individual proton signals to be identified without problems of overlap. The signal-to-noise ratio available from such techniques should enable their application to aqueous protein solutions using currently available high-field spectrometers.
Collapse
|
82
|
de Kruijff B, Morris GA, Cullis PR. Application of 31P-NMR saturation transfer techniques to investigate phospholipid motion and organization in model and biological membranes. BIOCHIMICA ET BIOPHYSICA ACTA 1980; 598:206-11. [PMID: 7417428 DOI: 10.1016/0005-2736(80)90281-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The potential of 31P-NMR saturation transfer experiments for determining motional characteristics (in the millisecond to second time scale) of phospholipids in model and biological membranes is demonstrated. A technique to separate membrane phospholipid 31P-NMR signals from those of small water-soluble phosphates in intact cells in liver tissue is also illustrated.
Collapse
|
83
|
Morris GA. Cold pack sling for the upper extremity. South Med J 1976; 69:962-3. [PMID: 941070 DOI: 10.1097/00007611-197607000-00054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
84
|
Abstract
Arthrography revealed an abnormal tract of contrast agent dissecting from the suprapatellar bursa into the soft tissue anterior to the patella and downward to a level 9 cm beneath the tibial plateau in a patient with complete rupture of the quadriceps tendon. The bursal anatomy of the anterior portion of the knee is reviewed in relation to the capsule-forming structures of the quadriceps expansion. The use of knee arthrography for the assessment of quadriceps tendon injury is advocated.
Collapse
|
85
|
Abstract
Radar cross-section measurements indicate that Ganymede scatters to Earth 12 percent of the power expected from a conducting sphere of the same size and distance. This compares with 8 percent for Mars, 12 percent for Venus, 6 percent for Mercury, and about 8 percent for the asteroid Toro. Furthermore, Ganymede is considerably rougher (to the scale of the wavelength used, 12.6 centimeters) than Mars, Venus, or Mercury. Roughness is made evident in this experiment by the presence of echoes away from the center of the disk. A perfectly smooth target would reflect only a glint from the center, whereas a very rough target would reflect power from over the entire disk.
Collapse
|
86
|
Lab MJ, Morris GA. A calliper for sampling relative movement of tissue surfaces. J Physiol 1972; 224:55P-56P. [PMID: 5071407 PMCID: PMC1331469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
|
87
|
Abstract
Radar observations of a narrow belt of the surface of Mars, centered at 16 degrees south latitude, show a very rugged terrain, with elevation differences greater than 13 kilometers from peak to valley. For nearby points, the relative altitude is measured to 40 meters at best; the precision is worse for points at different latitudes, or widely separated in longitude, because of orbital uncertainties. Some of the larger craters have been resolved, and their depth and, in some cases, the height of the raised rim have been measured. Where high resolution photographs, are available, the correlation is excellent.
Collapse
|