964 resultados para Selected-ion monitoring (SIM)
Resumo:
The temperature dependence of the X- and Q-band EPR spectra of Cs-2[Zn(H2O)(6)](ZrF6)(2) containing similar to1% Cu2+ is reported. All three molecular g-values vary with temperature, and their behavior is interpreted using a model in which the potential surface of the Jahn-Teller distorted Cu(H2O)(6)(2+) ion is perturbed by an orthorhombic strain induced by interactions with the surrounding lattice. The strain parameters are significantly smaller than those reported previously for the Cu(H2O)(6)(2+) ion in similar lattices. The temperature dependence of the two higher g-values suggests that in the present compound the lattice interactions change slightly with temperature. The crystal structure of the Cs-2[Zn(H2O)(6)](ZrF6)(2) host is reported, and the geometry of the Zn(H2O)(6)(2+) ion is correlated with lattice strain parameters derived from the EPR spectrum of the guest Cu2+ complex.
Resumo:
The selection, synthesis and chromatographic evaluation of a synthetic affinity adsorbent for human recombinant factor VIIa is described. The requirement for a metal ion-dependent immunoadsorbent step in the purification of the recombinant human clotting factor, FVIIa, has been obviated by using the X-ray crystallographic structure of the complex of tissue factor (TF) and Factor VIIa and has directed our combinatorial approach to select, synthesise and evaluate a rationally-selected affinity adsorbent from a limited library of putative ligands. The selected and optimised ligand comprises a triazine scaffold bis-substituted with 3-aminobenzoic acid and has been shown to bind selectively to FVIIa in a Ca2+-dependent manner. The adsorbent purifies FVIIa to almost identical purity (>99%), yield (99%), activation/degradation profile and impurity content (∼1000 ppm) as the current immunoadsorption process, while displaying a 10-fold higher static capacity and substantially higher reusability and durability. © 2002 Elsevier Science B.V. All rights reserved.
Resumo:
The majority of the world's population now resides in urban environments and information on the internal composition and dynamics of these environments is essential to enable preservation of certain standards of living. Remotely sensed data, especially the global coverage of moderate spatial resolution satellites such as Landsat, Indian Resource Satellite and Systeme Pour I'Observation de la Terre (SPOT), offer a highly useful data source for mapping the composition of these cities and examining their changes over time. The utility and range of applications for remotely sensed data in urban environments could be improved with a more appropriate conceptual model relating urban environments to the sampling resolutions of imaging sensors and processing routines. Hence, the aim of this work was to take the Vegetation-Impervious surface-Soil (VIS) model of urban composition and match it with the most appropriate image processing methodology to deliver information on VIS composition for urban environments. Several approaches were evaluated for mapping the urban composition of Brisbane city (south-cast Queensland, Australia) using Landsat 5 Thematic Mapper data and 1:5000 aerial photographs. The methods evaluated were: image classification; interpretation of aerial photographs; and constrained linear mixture analysis. Over 900 reference sample points on four transects were extracted from the aerial photographs and used as a basis to check output of the classification and mixture analysis. Distinctive zonations of VIS related to urban composition were found in the per-pixel classification and aggregated air-photo interpretation; however, significant spectral confusion also resulted between classes. In contrast, the VIS fraction images produced from the mixture analysis enabled distinctive densities of commercial, industrial and residential zones within the city to be clearly defined, based on their relative amount of vegetation cover. The soil fraction image served as an index for areas being (re)developed. The logical match of a low (L)-resolution, spectral mixture analysis approach with the moderate spatial resolution image data, ensured the processing model matched the spectrally heterogeneous nature of the urban environments at the scale of Landsat Thematic Mapper data.
Resumo:
MS/MS data derived from the [M-H](-) ions of desulfated caerulein peptides provide (i) sequencing information from a combination of alpha, beta and gamma backbone cleavages, and (ii) identification of specific amino acid side chains by side-chain cleavages [e.g. Ser (-CH2O), Thr (-CH3CHO) and Asp (-H2O)] (fragmentations having no counterparts in positive ion spectra). In addition, delta and/or gamma backbone cleavage ions from Asp residues identify the position of these residues in the peptide. In contrast, neither delta nor gamma cleavage ions are observed from either the Gln2 residue nor from Phe residues. Full structural information can be obtained from a consideration of the positive and negative ion MS/MS data in concert. Copyright (C) 2002 John Wiley Sons, Ltd.
Resumo:
Therapeutic drug monitoring of cyclosporin (CsA) has been established as part of the routine clinical treatment of patients following organ transplantation for more than 20 years, and based on contemporary knowledge, many consensus guidelines have been published to assist clinics and laboratories attain optimal strategies for patient care. This article addresses the newer directions in CsA monitoring, with particular reference to the Australasian situation that has evolved since the 1993 Australasian guideline (1). These changes have included the introduction of alternative assay methodologies, changed CsA formulation from Sandimmun to Neoral throughout Australasia, and alternatives to trough concentration (C0) monitoring, especially 2-hour concentration (C2) monitoring and associated validated dilution protocols to accurately quantitate the higher whole blood CsA concentrations. The revision was prepared following a recent survey of all Australasian CsA-monitoring laboratories (2) where discordant practices were evident.
Resumo:
Objective: To assess understanding of, and actual and potential roles in management of attention-deficit/hyperactivity disorder (ADHD) among GPs. Methods: A cross-sectional questionnaire survey of Queensland GPs selected randomly from the Royal Australian College of General Practitioners directory of members was carried out. Main outcome measures were knowledge levels of ADHD, current management practices, referral patterns and self-perceived information and training needs. Results: Three hundred and ninety-nine GPs returned a completed questionnaire (response rate 76%). Roles identified by GPs were: the provisional diagnosis of ADHD and referral to specialist services for confirmation of the diagnosis and initiation of management; assistance with monitoring progress once a management plan was in place; education of the child and their family regarding the disorder; and liaison with the school where necessary. Perceived barriers to increased involvement of GPs were: time and resource constraints of general practice; concerns regarding abuse and addiction liability of prescription stimulants; complex diagnostic issues associated with childhood behavioural problems; and lack of training and education regarding ADHD. Conclusions: General practitioners identify a role for themselves in ADHD care that is largely supportive in nature and involves close liaison with specialist services.
Resumo:
Indicators are valuable tools used to measure progress towards a desired health outcome. Increased awareness of the public health burden due to injury has lead to a concomitant interest in monitoring the impact of national initiatives that aim to reduce the size of the burden. Several injury indicators have now been proposed. This study examines the ability of each of the suggested indicators to reflect the nature and extent of the burden of non-fatal injury. A criterion validity, population-based, prospective cohort study was conducted in Brisbane, a sub-tropical Metropolitan City on the eastern seaboard of Australia, over a 12-month period between 1 January and 31 December 1998. Neither the presence of a long bone fracture nor the need for hospitalisation for 4 or more days were sensitive or specific indicators for 'serious' or major injury as defined by the 'Gold Standard' Injury Severity Score (ISS). Subsequent analysis, using other public health outcome measures demonstrated that the major component of the illness burden of injury was in fact due to 'minor' not serious injury. However, the suggested indicators demonstrated low sensitivity and specificity for these outcomes as well. The results of the study support the need to include at least all hospitalisations in any population-based measure of injury and not attempt to simplify the indicator to a more convenient measure aimed at identifying just those cases of,serious' injury.
Resumo:
The fundamental role of dendritic cells (DC in initiating and directing the primary immune response is well established. Furthermore, it is now accepted that DC may be useful in new vaccination strategies for preventing certain malignant and infectious diseases. As blood DC (BDC physiology differs from that of the DC homologues generated in vitro from monocyte precursors, it is becoming more relevant to consider BDC for therapeutic interventions. Until recently, protocols for the isolation of BDC were laborious and inefficient; therefore, their use for investigative cancer immunotherapy is not widespread. In this study, we carefully documented BDC counts, yields and subsets during apheresis (Cobe Spectra), the initial and essential procedure in creating a BDC isolation platform for cancer immunotherapy. We established that an automated software package (Version 6,0 AutoPBPC) provides an operator-independent reliable source of motionuclear cells (MNC for BDC preparation. Further, we observed that BDC might be recovered in high yields, often greater than 100% relative to the number of circulating BDC predicted by blood volume. An average of 66 million (range, 17-179) BDC per 10-1 procedure were obtained, largely satisfying the needs for immunization. Higher yields were possible on total processed blood volumes of 151. BDC were not activated by the isolation procedure and, more importantly, both BDC subsets (CD11c(+)CD123(low) and CD11c(-)CD123(high)) were equally represented. Finally, we established that the apheresis product could be used for antibody-based BDC immunoselection and demonstrated that fully functional BDC can be obtained by this procedure. (C) 2002 Published by Elsevier Science B.V.
Resumo:
Laboratory toxicity studies were conducted in southeastern Queensland, Australia, to determine the acute lethal effects of a 1-h pulse exposure of selected insecticides to adult and juvenile (
Resumo:
Protease-activated receptors type 2 (PAR2) are activated by serine proteases like trypsin and mast cell tryptase. The function and physiological significance of PAR2 receptors is poorly understood, but recent studies suggest a role during inflammatory processes in both airways and intestine. PAR2 receptors are also likely to participate in the control of ion transport in these tissues. We demonstrate that stimulation of PAR2 in airways and intestine significantly enhanced ion transport. Trypsin induced CI- secretion in both airways and intestine when added to the basolateral but not to the luminal side of these tissues. In both airways and intestine, stimulation of ion transport was largely dependent on the increase in intracellular Ca2+. Effects of trypsin were largely reduced by basolateral bumetanide and barium and by trypsin inhibitor. Thrombin, an activator of proteinase-activated receptors types 1, 3, and 4 had no effects on equivalent short-circuit current in either airways or intestine. Expression of PAR2 in colon and airways was further confirmed by reverse transcription-polymerase chain reaction. We postulate that these receptors play a significant role in the regulation of electrolyte transport, which might be important during inflammatory diseases of airways and intestine.
Resumo:
Proteinase-activated receptor (PAR) type 2 (PAR-2) has been shown to mediate ion secretion in cultured epithelial cells and rat jejunum. With the use of a microUssing chamber, we demonstrate the role of PAR-2 for ion transport in native human colonic mucosa obtained from 30 normal individuals and 11 cystic fibrosis (CF) patients. Trypsin induced Cl- secretion when added to the basolateral but not luminal side of normal epithelia. Activation of Cl- secretion by trypsin was inhibited by indomethacin and was further increased by cAMP in normal tissues but was not present in CF colon, indicating the requirement of luminal CF transmembrane conductance regulator. Effects of trypsin were largely reduced by low Cl-,by basolateral bumetanide, and in the presence of barium or clotrimazole, but not by tetrodotoxin. Furthermore, trypsin-induced secretion was inhibited by the Ca2+-ATPase inhibitor cyclopiazonic acid and in low-Ca2+ buffer. The effects of trypsin were almost abolished by trypsin inhibitor. Thrombin, an activator of PAR types 1, 3, and 4, had no effects on equivalent short-circuit currents. The presence of PAR-2 in human colon epithelium was confirmed by RT-PCR and additional experiments with PAR-2-activating peptide. PAR-2-mediated intestinal electrolyte secretion by release of mast cell tryptase and potentiation of PAR-2 expression by tumor necrosis factor-alpha may contribute to the hypersecretion observed in inflammatory processes such as chronic inflammatory bowel disease.