Articles: cations.
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Rapid Commun. Mass Spectrom. · Jan 2006
Combined use of gas chromatography and selected ion flow tube mass spectrometry for absolute trace gas quantification.
The value of the gas chromatography (GC) and selected ion flow tube mass spectrometry (SIFT-MS) combination for the analysis of trace gases is demonstrated by the quantification of acetone in air samples using the three precursor ions available to SIFT-MS, viz. H3O+, NO+ and O2+, and by the separation of the isomers 1-propanol and 2-propanol, and their analysis using H3O+ precursor ions. It is shown that the GC/SIFT-MS combination allows for accurate trace gas quantification obviating the regular, time-consuming calibrations that are usually required for the more commonly used detectors of GC systems, and the positive identification of isomers in mixtures that is often challenging using SIFT-MS alone. Thus, the GC/SIFT-MS combination paves the way to more confident analyses of complex mixtures such as exhaled breath.
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The WNK1 and WNK4 genes have been found to be mutated in some patients with hyperkalemia and hypertension caused by pseudohypoaldosteronism type II. The clue to the pathophysiology of pseudohypoaldosteronism type II was its striking therapeutic response to thiazide diuretics, which are known to block the sodium chloride cotransporter (NCC). Although this suggests a role for WNK1 in hypertension, the precise molecular mechanisms are largely unknown. ⋯ Moreover, SPAK and OSR1 were found to directly phosphorylate the N-terminal regulatory regions of cation-chloride-coupled cotransporters including NKCC1, NKCC2, and NCC. Phosphorylation of NCC was induced by hypotonic stress in cells. These results suggested that WNK1 and SPAK/OSR1 mediate the hypotonic stress signaling pathway to the transporters and may provide insights into the mechanisms by which WNK1 regulates ion balance.
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Closed system anaesthesia allows economic use of medical gases and volatile anaesthetics, maintenance of airway climatization and reduction of anaesthetic gas loss into the environment. In this context we reviewed papers addressing recent technical and clinical advances of closed system anaesthesia. ⋯ Modern feedback controlled ventilators allow the application of closed system anaesthesia as a safe and economic technique for routine clinical practice.
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Conduct of research involving humans in the intensive care unit (ICU) setting is complex and challenging. The vulnerable nature of critically ill patients raises issues of patient safety, and informed consent is difficult. With an increasing global interest in human research ethics, broadened government mandates have targeted improvements in research participant protection and research governance. ⋯ We have developed An Ethics Handbook for Researchers (EH) for the ANZICS CTG for intended use by researchers in Australian and New Zealand ICUs. The purpose of the EH is to act as a practical advisory guide/supplement; to add clarification regarding ethical issues specific to intensive care research, to assist in the expedition of ethics committee research submission and to summarise available useful resources. This article introduces a précis of key issues from the EH including specific ethical difficulties pertaining to ICU research, a summary of the process by which ethics committee decisions in Australia and New Zealand are informed, and the use of ethical checklists to assist researchers.
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Skull Base Interd Ap · Nov 2005
Radiographic imaging of the distal dural ring for determining the intradural or extradural location of aneurysms.
The effectiveness of several anatomical and radiological landmarks proposed to determine whether an aneurysm is located intradurally or extradurally is still debated. In anatomical and radiological studies, we examined the relationships of the distal dural ring (DDR) to the internal carotid artery (ICA) and surrounding bony structures to aid in the localization of aneurysms near the DDR. Anatomical relationships were examined by performing dissections on 10 specimens (5 formalin-fixed cadaveric heads). ⋯ On 50 dry skulls, we measured the vertical distance between the planum sphenoidale and medial aspect of the optic strut (5.0 +/- 0.4 mm), the interoptic strut distance (14.4 +/- 1.4 mm), and the linear distance between the most posterior aspect of the planum sphenoidale (limbus sphenoidale) and the tuberculum sellae (6.0 +/- 0.5 mm). Using these measurements and the planum sphenoidale, tuberculum sellae, and optic strut as reference landmarks, we determined the location of the aneurysm relative to the DDR on angiographic images. In this way, we were able to identify whether lesions were intra- or extradural.