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Biomedical subjects

R Bateman

Publications and source records attributed to R Bateman.

17 recordsLinked to original sources
PubMed2005

Case report: Use of a remifentanil infusion with the tri-service anaesthetic apparatus.

During a recent deployment to Iraq, it was noticed that patients' recovery times from general anaesthesia were significantly prolonged. We postulated that this was because of a lack of nitrous oxide--thereby creating a requirement for greater concentrations of volatile agent to maintain adequate depth of anaesthesia. We chose to adopt the technique of running a remifentanil infusion with the Tri-Service apparatus in an attempt to reduce the administered volatile and thus shorten recovery times.

Adult↗
PubMed2004

Fact and fantasy.

Explore the source record for details and available documents.

Anti-Bacterial Agents↗
PubMed2001

Accurate mass liquid chromatography/mass spectrometry on quadrupole orthogonal acceleration time-of-flight mass analyzers using switching between separate sample and reference sprays. 2. Applications using the dual-electrospray ion source.

A new electrospray dual sprayer, LockSpray, was developed for accurate mass measurements on a quadrupole orthogonal acceleration time-of-flight mass spectrometer (oa-Q-ToF). With the dual-sprayer ion source, both sprays are orthogonal to each other. A mechanism similar to the one employed on the multiplexed electrospray source (MUX) allows switching between reference and sample sprayer. The reference sprayer is optimized for low flow rates, whereas the sample sprayer is a conventional Z-spray type sprayer. Earlier work using a modified MUX ion source on an orthogonal acceleration time-of-flight instrument showed promising results. In this paper, examples obtained with the LockSpray, specifically designed for accurate mass measurements on an oa-Q-ToF, are presented. The examples include results obtained for the identification of impurities in drug substances such as cimetidine and rosiglitazone, using accurate mass tandem mass spectrometry in both positive and negative ion electrospray modes. Good mass accuracies, i.e., within 2 mDa of the theoretical value, were obtained in MS and MS/MS operation.

Calibration↗
PubMed2001

Long-range magnetic order in Mn[N(CN)2]2(pyz) (pyz = pyrazine). Susceptibility, magnetization, specific heat, and neutron diffraction measurements and electronic structure calculations.

Using dc magnetization, ac susceptibility, specific heat, and neutron diffraction, we have studied the magnetic properties of Mn[N(CN)2]2(pyz) (pyz = pyrazine) in detail. The material crystallizes in the monoclinic space group P2(1)/n with a = 7.3248(2), b = 16.7369(4), and c = 8.7905 (2) A, beta = 89.596 (2) degrees, V = 1077.65(7) A(3), and Z = 4, as determined by Rietveld refinement of neutron powder diffraction data at 1.35 K. The 5 K neutron powder diffraction data reflect very little variation in the crystal structure. Interpenetrating ReO3-like networks are formed from axially elongated Mn(2+) octahedra and edges made up of mu-bonded [N(CN)2](-) anions and neutral pyz ligands. A three-dimensional antiferromagnetic ordering occurs below T(N) = 2.53(2) K. The magnetic unit cell is double the nuclear one along the a- and c-axes, giving the (1/2, 0, 1/2) superstructure. The crystallographic and antiferromagnetic structures are commensurate and consist of collinear Mn(2+) moments, each with a magnitude of 4.15(6) mu(B) aligned parallel to the a-direction (Mn-pyz-Mn chains). Electronic structure calculations indicate that the exchange interaction is much stronger along the Mn-pyz-Mn chain axis than along the Mn-NCNCN-Mn axes by a factor of approximately 40, giving rise to a predominantly one-dimensional magnetic system. Thus, the variable-temperature magnetic susceptibility data are well described by a Heisenberg antiferromagnetic chain model, giving g = 2.01(1) and J/k(B) = -0.27(1) K. Owing to single-ion anisotropy of the Mn(2+) ion, field-induced phenomena ascribed to spin-flop and paramagnetic transitions are observed at 0.43 and 2.83 T, respectively.

Journal Article↗
PubMed2001

Facile sequencing of oligosaccharides by matrix-assisted laser desorption/ionisation on a hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometer.

N-Linked oligosaccharide mixtures released from a number of standard glycoproteins were derivatised with 3-acetylamino-6-acetylaminoacridine (AA-Ac) using reductive amination. Analysis of these mixtures using an experimental matrix-assisted laser desorption/ionisation (MALDI) hybrid quadrupole orthogonal acceleration time-of-flight (Q-TOF) mass spectrometer provided detailed information about the mass distribution of the glycan derivatives. Collision-induced dissociation of the singly protonated [M + H](+) ions also gave rise to a number of product ions produced by the sequential cleavage of the glycosidic linkages. As fragmentation of the positively charged species occurred predominantly in one direction, i.e., from the non-reducing end of the glycan to the AA-Ac moiety, a considerable amount of information could be obtained with ease about the sequence in which the sugar residues were attached to one another. This derivatisation procedure and mass spectrometric methodology were applied successfully to neutral and acidic glycans released from proteins separated by gel electrophoresis.

Carbohydrate Sequence↗
PubMed2001

The benefits of using customized procedure packs.

Discrete item purchasing is the traditional approach for hospitals to obtain consumable supplies for theatre procedures. Although most items are relatively low cost, the management and co-ordination of the supply chain, raising orders, controlling stock, picking and delivering to each operating theatre can be complex and costly. Customized procedure packs provide a solution.

Cost-Benefit Analysis↗
PubMed2000

Accurate mass liquid chromatography/mass spectrometry on orthogonal acceleration time-of-flight mass analyzers using switching between separate sample and reference sprays. 1. Proof of concept.

This paper describes the use of two separate electrosprays for introducing sample and reference for accurate mass liquid chromatography/mass spectrometry (LC/MS) on an orthogonal acceleration time-of-flight mass analyzer. This is carried out using an adaptation of the multiplexed electrospray ion source in which only two of the sprays are utilized. Results are shown for the positive ion detection of trace-level components in complex matrixes and good mass accuracies are obtained, even for very low level components. An example of accurate mass measurements obtained using negative ion LC/MS is also shown. To obtain additional structural information, an example of cone voltage fragmentation is included and shows that good mass accuracy can be obtained for both precursor and fragment ions.

Chromatography, Liquid↗
PubMed1999

High throughput liquid chromatography/mass spectrometric analyses using a novel multiplexed electrospray interface.

A novel four- channel multiplexed electrospray liquid chromatography interface is described. This device has been used to analyse both single components and mixtures by liquid chromatography/mass spectrometry (LC/MS) as well as synthetic samples prepared by automated procedures. These data provided unambiguous molecular weight assignments to both major components and synthetic by-products in these samples. In this work particular attention has also been paid to the elimination of interchannel crosstalk. Copyright 1999 John Wiley & Sons, Ltd.

Journal Article↗
PubMed1999

The role of destruxins in the pathogenicity of metarhizium anisopliae for three species of insect

The entomopathogenic fungus Metarhizium anisopliae var anisopliae produces a family of cyclic peptide toxins, destruxins (DTX), both in culture and in vivo in mycosed insects. The contribution of these insecticidal toxins to the disease process has been investigated in the tobacco hornworm, Manduca sexta (Lepidoptera), the desert locust, Schistocerca gregaria (Orthoptera), and the vine weevil, Otiorhynchus sulcatus (Coleoptera). A significant negative correlation was found between the titer of DTX production in vitro of isolates of M. anisopliae var anisopliae pathogenic for Otiorhynchus and the median lethal time, suggesting a role for the toxin in isolate virulence. The same was true for Manduca-active isolates. A key exception was isolate 703. This is highly virulent for M. sexta, yet does not produce DTX in vitro, grows largely as hyphal fragments in the hemolymph of infected insects, and does not cause host paralysis. These results are discussed in the light of the hypothesis that there are at least two possible virulence strategies among isolates of M. anisopliae var anisopliae pathogenic for Manduca viz the "toxin strategy" and the "growth strategy." For locusts, a strong positive correlation was found only between in vitro toxin production and percentage mortality of individuals in which sporulation did not occur on the cadaver. To account for this, it is suggested that if DTX kills locusts before the fungus has established itself, then the pathogen may not compete effectively with the saprophytic flora and, as a result, fails to sporulate. It is concluded that, in the pathogenesis of M. anisopliae var anisopliae for all three insects, there is a relationship between the titer of DTX production of isolates in vitro and the killing power. Copyright 1999 Academic Press.

Journal Article↗
PubMed1999

Accident prevention in the A&E department.

Accident and Emergency units are often regarded as the 'shop window' of a health service. While the priority is to attend to those in need of emergency services, there may also be opportunities for health education amongst a 'captive audience', particularly in relation to accident prevention. This report illustrates how the influence of one A&E department was used amongst primary school children to increase their awareness of cycle safety. Educational materials were developed, a series of visits to schools was planned, which over 600 children attended, and a competition organised. Initial responses from the children were very positive, and an analysis of subsequent cycle injury levels is now under way. The project formed part of a wide ranging practice development programme within a large district general hospital in Whitehaven in collaboration with St Martin's College Department of Nursing. It combined the need to develop quality services and staff in tandem. The outreach educational approach is now being examined for adoption in other areas of the Trust.

Accident Prevention↗
PubMed1998

Localization of O-glycosylation sites of MUC1 tandem repeats by QTOF ESI mass spectrometry.

The potential of electrospray mass spectrometry (ESMS) for the sequencing of glycopeptides was evaluated using quadrupole time-of-flight (QTOF) technology in the MS/MS mode. The location of O-glycosylation sites was possible in the positive ion (+) mode by detection of prominent y- and b-fragment ions from the underivatized TAP25-2 [T1APPAHGVT9S10APDT14RPAPGS20T21APPA], an overlapping sequence of MUC1 tandem repeats which had been glycosylated in vitro by two GalNAc residues in the positions T9 and T21. The high mass resolution and accuracy of QTOF-(+)ESMS allowed reliable structural assignments. The reduced complexity of the fragment spectra and the higher signal-to-noise ratio render QTOF-(+)ESMS an alternative mass spectrometric approach to the identification of O-glycosylation sites when compared with sequencing by post-source decay matrix-assisted laser desorption/ionization MS. Diagnostic ions from the N-terminus in the b-series offered direct evidence, which was supported by indirect evidence from the C-terminus ions of the y-series. The higher glycosylated GalNAc2-substituted fragments were mainly observed as multiply ionized species.

Amino Acid Sequence↗
PubMed1998

Dissection of multi-protein complexes using mass spectrometry: subunit interactions in transthyretin and retinol-binding protein complexes.

Complexes formed between transthyretin and retinol-binding protein prevent loss of retinol from the body through glomerular filtration. The interactions between these proteins have been examined by electrospray ionization combined with time-of-flight mass analysis. Conditions were found whereby complexes of these proteins, containing from four to six protein molecules with up to two ligands, are preserved in the gas phase. Analysis of the mass spectra of these multimeric species gives the overall stoichiometry of the protein subunits and provides estimates for solution dissociation constants of 1.9 +/- 1.0 x 10(-7) M for the first and 3.5 +/- 1.0 x 10(-5) M for the second retinol-binding protein molecule bound to a transthyretin tetramer. Dissociation of these protein assemblies within the gas phase of the mass spectrometer shows that each retinol-binding protein molecule interacts with three transthyretin molecules. Mass spectral analysis illustrates not only a correlation with solution behavior and crystallographic data of a closely related protein complex but also exemplifies a general method for analysis of multi-protein assemblies.

Animals↗
PubMed1998

Role of cuticle-degrading proteases in the virulence of metarhizium spp. for the desert locust, schistocerca gregaria

The production of the subtilisin proteinase, PR1, and the trypsin-like enzyme, PR2, in liquid cultures of 19 isolates of Metarhizium spp. was investigated. PR1 activity was generally observed 72 h after inoculation whilst PR2 activity was detected in most strains 48 h after inoculation. PR1 was partially purified from each isolate of Metarhizium spp. The ability of this enzyme from each isolate to degrade different types of insect cuticle was investigated. The cuticle types used were Manduca sexta pupal cuticle, adult desert locust (Schistocerca gregaria) wing cuticle, abdominal cuticle, and pharate adult locust abdominal cuticle. These cuticle types differ in their protein composition and degree of sclerotization. PR1 hydrolyzed the locust cuticle to different degrees. The data suggest a hierarchy for the susceptibility to hydrolysis in the order pharate adult abdominal > adult abdominal > wing. There was no significant correlation between the ability of the enzymes to degrade any of the cuticle types and median lethal time of the isolates against the desert locust. However, a correlation was found between the ability of enzymes to hydrolyze different locust cuticles. Such correlations were not apparent to the same extent between M. sexta cuticle and the locust cuticles. These results are discussed in terms of a possible contribution of PR1 to host specificity. Copyright 1998 Academic Press.

Journal Article↗
PubMed1993

Measurement of red blood cell-vitamin B12: a study of the correlation between intracellular B12 content and concentrations of plasma holotranscobalamin II.

We have recently reported a new and rapid assay to measure plasma holotranscobalamin II (holo TC II) as a means of exploring vitamin B12 status. In order to further evaluate the significance of plasma holoTC II in determining tissue cobalamin, we have chosen the red blood cell-vitamin B12 (RBC-B12) assay as a measure of tissue vitamin B12 content and studied the relationship between RBC-B12 and plasma holoTC II levels. Plasma holoTC II and RBC-B12 concentrations were concomitantly assayed in 20 hematologically normal controls and cancer patients. In our groups of controls, the mean value of RBC-B12 was determined as 241 +/- 51 pg/ml of packed erythrocytes (PE) with a range varying from 180 to 355 pg/ml PE. Preliminary results obtained in 32 cancer patients revealed lower holoTC II and RBC-B12 levels than the control group and a required threshold value of 70 pg/ml of holoTC II in order to maintain a normal RBC-B12 greater than 180 pg/ml PE.

Erythrocytes↗