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Biomedical subjects

I Jardine

Publications and source records attributed to I Jardine.

At least 19 recordsLinked to original sources
PubMed2001

Erythrocyte spectrin is an E2 ubiquitin conjugating enzyme.

The involvement of red blood cell spectrin in the ubiquitination process was studied. Spectrin was found to form two ubiquitin-associated derivatives, a DTT-sensitive ubiquitin adduct and a DTT-insensitive conjugate, characteristic intermediate and final products of the ubiquitination reaction cascade. In addition to spectrin and ubiquitin, ubiquitin-activating enzyme (E1) and ATP were necessary and sufficient to form both the spectrin-ubiquitin adduct and conjugate. No exogenous ubiquitin-conjugating (E2) or ligase (E3) activities were required, suggesting that erythrocyte spectrin is an E2 ubiquitin-conjugating enzyme able to target itself. Both ubiquitin adduct and conjugate were linked to the alpha subunit of spectrin, suggesting that the ubiquitin-conjugating (UBC) domain and its target regions reside on the same subunit.

Adenosine Triphosphate↗
PubMed2001

Telemedicine options appraisal for a health district--a strategic clinical and business case.

A clinical and business plan examined five areas in which telemedicine could be introduced to support the strategic objectives of a large health authority: coronary heart disease; links between community hospitals and local care centres and acute hospitals; store-and-forward consultations; care in the community; and mental health. The plan identified substantial clinical, organizational and economic potential benefits, which were greatest when a radical re-engineering of the service was envisaged. Similar studies in other health districts would help to test these conclusions and inform future health service planning.

Community Health Services↗
PubMed2001

The potential for telemedicine to improve coronary heart disease services.

The potential of telemedicine to improve services for patients suffering from coronary heart disease (CHD) was explored. Key issues surrounding the delivery of CHD services in London were identified, such as a shortage of skilled staff, the need for appropriate patient information and problems with waiting times, particularly for diagnostic test results. Telemedicine has the potential to improve service delivery in each of these areas. It is unlikely that some of the targets for CHD service delivery set out by the Department of Health's National Service Frameworks can be met without the use of telemedicine.

Attitude of Health Personnel↗
PubMed2000

The potential for telemedicine and telecare in Deptford.

We carried out a study to explore the potential of telemedicine and telecare to improve health-care for the population served by a health centre based in Deptford in south-east London. A wide range of potentially useful telemedicine and telecare applications was identified, nine of which could provide some immediate benefit. Other requiring new approaches to the delivery of care involved some reengineering of services. Some suggestions focused on the need to integrate information technology with service provision. Other suggestions raised strategic questions, the most important of which concerned the routes of access to health-care.

Delivery of Health Care↗
PubMed1998

Application of liquid chromatography-mass spectrometry(n) analyses to the characterization of novel glyburide metabolites formed in vitro.

The application of bench-top ion-trap atmospheric pressure ionization mass spectrometry in the characterization of in vitro metabolites of glyburide is discussed. The metabolites formed in vitro by rat, dog, monkey and human liver microsomes were separated by reversed-phase high-performance liquid chromatography (HPLC) and characterized by mass spectrometry (MS)n experiments. The utility of data dependent MS1-MS2-MS3 analyses, where the mass spectrometer makes "real-time" decisions about the experiment to be performed, are described using the characterization of two novel metabolites of glyburide as an example. The metabolite profiles from each species were similar. Six cyclohexyl hydroxylation products were detected, as well as two novel monooxygenation products formed via hydroxylation of the ethyl chain at the benzylic position, and alpha to the amide nitrogen. The ion-trap with electrospray ionization proved to be a sensitive and reliable HPLC detection system that provided important chemical structure information.

Animals↗
PubMed1997

Drug quantitation on a benchtop liquid chromatography-tandem mass spectrometry system.

The specificity and selectivity of LC-MS-MS is illustrated to explain why LC-MS-MS has become the method of choice for quantitation within the pharmaceutical industry. Two assays are described that demonstrate the facility with which new ion trap technology can utilize the selectivity and sensitivity of LC-MS-MS to quantitate trace level components within complex matrices, in particular human plasma. One assay undergoes a validation procedure and demonstrates the utility of this new technology for drug quantitation within a regulated environment.

Calibration↗
PubMed1996

Quadrupole ion trap mass spectrometry.

A number of other features of ITMS systems that will enhance their ability to analyze biological macromolecules are worth mentioning. As has already been demonstrated for ESI/quadrupole, ESI/magnetic sector, and ESI/FTICR systems, the capability of inducing fragmentation of the ESI-generated multiply charged ions of biological macromolecules in the capillary/skimmer region of the ESI source and subsequently selectively analyzing fragments can also be carried out with the QITMS, as we have demonstrated using bovine serum albumin (data not shown). The ability to carry out chemical reactions on biological macromolecules inside the QITMS has been demonstrated by McCluckey et al. by showing that the introduction of a pulse of volatile base, such as diethylamine, can result in proton removal from multiply charged protein ions, resulting in species with lower charge states. The application of the technique of deuterium exchange of active hydrogens on peptides to simplify the interpretation of MS/MS sequencing experiments can be implemented for ESI/QITMS. Carrying out such exchange inside the ITMS may also be possible, with resulting analytical advantages. Reports of a hybrid QITMS-TOF system, which was operated with either ESI or MALDI methodology, and which demonstrated low femtomolar sensitivity with higher resolution of the TOF analyzer because of ion injection of essentially monoenergetic ions from the QITMS into the TOF, illustrate additional uses of the QITMS. The reverse combination (e.g., ESI/TOF/QITMS or MALDI/TOF/QITMS) could afford preselection of ions for even higher performance in the QITMS, because space charging (loss of performance such as resolution because of too much charge in close proximity in the ion trap) would be minimized. Opportunities for the application of QITMS technology for the analysis of biological macromolecules abound, including ultrahigh-sensitivity protein sequencing using specifically derivatized amino acids released by Edman chemistry; rapid sequencing of MHC-associated antigenic peptides of variable length (approximately nonamers for the MHC I complexes to > dodecamers for the MHC II complexes), which are available in only very low amounts (femtomole/attomole) and in very complex mixtures (5000-10,000 species) of closely related peptide structures; ultrahigh-sensitivity analysis of peptides and proteins directly in vivo using microelectrospray; direct analysis of metal ion binding to peptides and proteins and analysis of noncovalent interactions, including conformation; and possible analysis of plasmid DNA, as has been suggested by ESI ionization of a 2-MDa DNA species. In summary, the ability of the QITMS to interface to key separations systems such as HPLC and HPCE through the critical ionization techniques of ESI and MALDI, coupled with the high mass range, high mass resolution, high sensitivity, high-efficiency CID, and MS capabilities of this device, will provide an astonishing array of cost-effective capabilities for the qualitative and quantitative analysis of biological macromolecules.

Amino Acid Sequence↗
PubMed1993

Rapid high-sensitivity peptide mapping by liquid chromatography-mass spectrometry.

Toward a complete LC-MS mapping system for peptides and proteins, we have coupled a precision-flow microbore HPLC system to an electrospray single quadrupole mass spectrometer. The HPLC system allows fast separation of protein digests with UV detection at the low pmol level. A 2 microliters/min portion (1:25) of the effluent is passed into a high-sensitivity electrospray MS system. The electrospray source allows for molecular mass associated ions (MH+, MH2(2+), MH3(3+), etc.) to be generated as well as collision induced dissociation of these ions before MS analysis. After LC-MS runs, with or without partial fragmentation, the data generated are largely interpreted by identification of predicted peptides, incompletely digested peptides, unusual peptide cleavages, and so on, using appropriate integrated software (PEPMAP, PEPMATCH). Examples of peptide mapping at the low pmol level using this integrated system will be shown (e.g., of the protein human growth hormone and of the glycoprotein, tissue plasminogen activator).

Amino Acid Sequence↗
PubMed1991

Mass spectrometry software for biochemical analysis in electrospray and fast atom bombardment modes.

New mass spectrometry techniques, such as electrospray ionization (ESI), allow the study of large biomolecules and peptide mixtures. The data produced are complex and interpretation can be a long and tedious process. A new suite of data-processing software is described which allows many of these operations to be carried out in a rapid, automated way. Software is described for the deconvolution of the spectra of multiply charged ions, for both pure compounds and mixtures. The rapid peptide mapping of protein digests from h.p.l.c.-m.s. data and peptide sequence confirmation from multiple-stage (MS)-m.s. data using tandem quadrupole m.s. are also described. In addition preliminary results are presented on first principle sequencing of unknown peptides from MS-m.s. experiments.

Amino Acid Sequence↗
PubMed1989

Plasma desorption mass spectrometric analysis of mycobacterial glycolipids.

Mycobacteria are characterized by species- or type-specific glycolipid antigens. These are generally of the following three types: the trehalose-containing, acylated lipooligosaccharides (LOS), the C-mycoside glycopeptidolipids (GPL), and the phenolic glycolipids (PGL). To date, convenient mass spectrometric analysis of the intact form of these complex glycolipids has proved to be difficult. The successful plasma desorption mass spectrometric analysis of intact mycobacterial glycolipids of the LOS, GPL, and PGL types is now reported, allowing location of the acyl residues and providing oligosaccharide sequence and molecular weight information.

Chemical Phenomena↗
PubMed1989

Rapid identification of calbindin-D28k cyanogen bromide peptide fragments by plasma desorption mass spectrometry.

Chicken intestinal calbindin-D28k is an intracellular protein which is believed to have a fundamental role in vitamin D-mediated transport of calcium. A mapping approach based on 252Cf plasma desorption mass spectrometry (PD mapping) was used to screen the DNA-deduced sequence of calbindin-D28k for sequence changes and post-translational modifications. In the PD mapping experiment, purified calbindin-D28k was cleaved with cyanogen bromide and the resulting peptides were subjected to PD mass spectrometric analysis either as a mixture or as high-performance liquid chromatography isolated fractions. The DNA-derived primary structure of calbindin-D28k was confirmed by rapid PD mass spectral identification of the CNBr peptide fragments, and the nature of the N-terminal blocking group was readily determined to be an acetyl group. The relatively non-destructive nature of the PD mass spectrometric analysis allowed the mapping of the N-terminal peptide through an additional in situ V8 protease enzymatic reaction.

Amino Acid Sequence↗
PubMed1989

Identification of the convulsant opiate thebaine in mammalian brain.

The convulsant opiate thebaine, an intermediate of morphine biosynthesis, was purified from bovine brain to homogeneity by gel filtration and high-performance liquid chromatography (HPLC) monitored by a radioimmunoassay. The immunoreactive material behaved identically to standard thebaine in two HPLC systems and was confirmed to be thebaine by combined gas chromatography/mass spectrometry. To our knowledge, the presence of thebaine in mammalian tissue has not been demonstrated previously. Codeine and morphine were also found to exist in ovine brain. The presence of thebaine in ovine brain provides strong evidence that morphine and codeine, in various mammalian tissues, are of endogenous origin and actually biosynthesized from a precursor.

Animals↗
PubMed1989

Structure and function of mycobacterial glycolipids and glycopeptidolipids.

Earlier work from this and other laboratories has revealed the presence within Mycobacterium spp. of three classes of glycolipid antigens which we have called the glycopeptidolipids, the lipooligosaccharides and the phenolic glycolipids. Representative structures of each from different species and sub-species have been proposed. More recently, new variants of these antigens and older structures have been analyzed by Fourier transform infrared, NMR, particularly at high temperatures, and, most notably, by fast atom bombardment and Californium desorption mass spectrometry. Extraordinary novelty and diversity were revealed, particularly at the distal non-reducing end of the oligosaccharide chains, marked by the presence of new branched-chain sugars, amino sugars and sugar acids. These epitopes and monoclonal antibodies to them have been used for the critical identification of mycobacteria. In addition, the pure antigens are the basis of specific serological tests for various mycobacterioses. The resurgence of interest in "atypical" mycobacteria stems from their occurrence as opportunistic pathogens in many patients with acquired immunodeficiency syndrome, although they have long been associated with pulmonary and other organ infections. Foremost among these mycobacteria are serovars of the Mycobacterium avium-Mycobacterium intracellulare complex (the M. avium complex). The surface antigens which differentiate these serovars are glycopeptidolipids, related to "mycoside C" and, accordingly, composed of a glycosylated lipopeptide "core", fatty acyl-D-Phe-D-alloThr-D-Ala-L-acanyl-O- (3,4-di-O-methyl-alpha-L-rhamnopyranoside), to which a haptenic oligosaccharide is linked at the threonine substituent; this oligoglycosyl unit is the source of type specificity.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Further novel amido sugars within the glycopeptidolipid antigens of Mycobacterium avium.

The individual serovars of the Mycobacterium avium complex, a source of serious and persistent infections in individuals with underlying immune deficiencies, also present an extraordinary set of novel sugar epitopes as part of their type-specific glycopeptidolipid surface antigens. Californium desorption-mass spectrometry has been successfully applied to the holistic glycopeptidolipid antigen of M. avium serovar 12 and its per-O-acetyl derivative, to arrive at the following structure, of molecular mass 1876: (Sequence: see text). The pentasaccharide hapten, released as the tetraglycosyl alditol, was subjected to methylation analysis, absolute configurational analysis, 1H NMR and fast atom bombardment-mass spectrometry to arrive at the structure: 4-(2'-Hydroxy) propionamido-4,6-dideoxy-3-O-Me-Glcp (beta 1----3)-4-O-Me-L-Rhap (alpha 1----3)-L-Rhap (alpha 1----3)-L-Rhap (alpha 1----2)-6-deoxytalitol. Two-dimensional proton correlation spectroscopy was also applied to determine the configuration of the unique distal segment of the oligosaccharide unit. The significance of this structure in the context of the fully elucidated structures of the antigens from 12 of the 31-member M. avium complex is discussed.

Antigens, Bacterial↗
PubMed1988

Peptide and protein mapping by 252Cf-plasma desorption mass spectrometry.

The mapping of peptide digests by using fast atom bombardment mass spectrometry for evaluating the correctness of known or expected protein sequences is a well-established strategy. A similar approach ("PD mapping") is described which utilizes 252Cf-plasma desorption mass spectrometry (PDMS). This PD mapping approach is demonstrated and evaluated by screening the DNA-deduced sequences of recombinant interleukin-2 and human growth hormone. In the PD mapping experiment, the protein is cleaved either chemically or enzymatically and the molecular weights of the peptides predicted from the proposed amino acid sequence are compared with those determined mass spectrometrically. The relatively nondestructive nature of the PD mass spectrometric analysis allows further confirmation of the sequence assignments of individual peptides through additional steps of enzymatic or chemical modification on the nitrocellulose-bound peptides. The PD mapping method is both fast and sensitive, requiring only low nanomole amounts per map.

Amino Acid Sequence↗