Search results for "DETECT"
showing 10 items of 5902 documents
Application of headspace solid phase dynamic extraction gas chromatography/mass spectrometry (HS-SPDE-GC/MS) for biomonitoring of n-heptane and its m…
2011
Abstract Solid phase dynamic extraction (SPDE) is an innovative sample preparation and enrichment technique in connection with gas chromatography (GC). Using SPDE, we developed a method for simultaneous determination of n-heptane and its mono-oxygenated metabolites heptane-4-one, 3-one, 2-one, 4-ol, 3-ol, 2-ol, and 1-ol in blood. After adjustment of various extraction and desorption parameters, method validation resulted in limits of detection (LOD) between 0.006 (heptane-4-one) and 0.021 mg/L (heptane-1-ol). Intra-assay coefficients of variation ranged between 4.8% and 20.8% while relative recovery ranged between 100% and 117% (spiked concentration 0.128 mg/L, n = 8). The method was appli…
Magnetic molecularly imprinted polymers for the selective determination of cocaine by ion mobility spectrometry
2018
Abstract Magnetic molecularly imprinted polymers (MMIPs) were prepared for cocaine recognition by bulk polymerization in the presence of magnetic nanoparticles (MNPs). Two reagents (polyethylene glycol (PEG) and 3-(trimethoxysilyl)propyl methacrylate (V)) were used for MNPs modification. MMIPs were characterized and compared in terms of loading capacity, reusability, accuracy and precision for the extraction of cocaine from saliva samples. It was observed that V-MMIPs gave higher physical stability than PEG-MMIPs. Thus, V-MMIP were used for the analysis of cocaine users saliva. The developed procedure based on ion mobility spectrometry (IMS) provided limits of detection and quantification o…
Prospective, blinded comparison of cytology and DNA-image cytometry of brush biopsies for early detection of oral malignancy
2012
summary Objectives: Adjunctive techniques like DNA image cytometry (DNA-ICM) have been attributed to enhance the diagnostic performance of oral brush biopsies. The aim of the study was an evaluation of brush biopsies, analysed according to morphological criteria and by DNA-ICM vs. histological findings in a blinded prospective trial. Materials and methods: Eighty eight brush biopsies of 70 patients were sampled. Only clinical suspicious but not evident malignant oral lesions were included. Clinical diagnosis was leukoplakia (n = 36), lichen planus (n = 18), verruciform erythroplakia (n = 12), erythroleukoplakia (n = 9), erosion (n = 7) and induration (n = 6). Evaluation was conducted via hi…
Towards optimal clinical and epidemiological registration of haematological malignancies: Guidelines for recording progressions, transformations and …
2015
AbstractHaematological malignancies (HM) represent over 6% of the total cancer incidence in Europe and affect all ages, ranging between 45% of all cancers in children and 7% in the elderly. Thirty per cent of childhood cancer deaths are due to HM, 8% in the elderly. Their registration presents specific challenges, mainly because HM may transform or progress in the course of the disease into other types of HM. In the context of cancer registration decisions have to be made about classifying subsequent notifications on the same patient as the same tumour (progression), a transformation or a new tumour registration. Allocation of incidence date and method of diagnosis must also be standardised…
How do international gastric cancer prevention guidelines influence clinical practice globally?
2020
Clinical guidelines recommend particular approaches, including 'screen-and-treat' strategy for Helicobacter pylori, to prevent gastric cancer. However, little of this is implemented in clinical practice. The aim of the study was to identify barriers to implementation of international guidelines. A web-based questionnaire distributed globally to specialists in the field. Altogether 886 responses from 75 countries were received. Of the responders, 570 (64%) were men of mean age 47 years. There were 606 gastroenterologists and 65 epidemiologists among the responders. Altogether, 79.8% of the responders disagreed that the burden of gastric cancer is a diminishing problem. 'Screen-and-treat' str…
Ultrasound-guided fine-needle aspiration cytology in the early detection of melanoma metastases.
2000
BACKGROUND. The early detection and treatment of tumor recurrences in melanoma patients is dependent on reliable, sensitive, and specific techniques to verify suspected tumor metastases. As of now, fine-needle aspiration cytology (FNAC) has yet to establish itself in the routine follow-up of melanoma patients. METHODS. FNAC procedures were performed in melanoma patients with palpable tumors or nonpalpable, ultrasonically suspicious lesions. Cytodiagnostic evaluation of fine-needle samples obtained from suspicious lesions was performed morphologically. Findings were validated either by histopathologic diagnosis or prolonged clinical follow-up. RESULTS. The cytologic examination of 739 FNACs …
Noninvasive double confirmation of cocaine abuse.
2013
A double confirmation procedure, based on the combined application of Ion Mobility Spectrometry (IMS) and Infrared Spectroscopy (IR), has been developed for the noninvasive unambiguous identification of cocaine consume. The use of nasal mucus as a biological specimen for cocaine abuse confirmation has been proposed as an alternative to the use of blood and urine due to its noninvasive character and the presence of the parent compound instead of its metabolites. Sampling conditions, interferences caused by cutting agents and other substances, and limits of identification (LOI) and confirmation (LOC) have been deeply evaluated. The procedure combines the high sensitivity of the IMS to identif…
Development and validation of a reliable method for studying the distribution pattern for opiates metabolites in brain
2012
Abstract Brain distribution pattern of “street” heroin metabolites (morphine and codeine) was investigated in two fatalities due to “acute narcotism”. A suitable sample pretreatment prior to solid-phase-extraction was developed to achieve a good recovery of the analytes and to eliminate the interfering species. After derivatization with MSTFA, samples were analyzed by GC/MS. Specificity, accuracy, precision and linearity of the method were evaluated; LOD and LOQ were, respectively, 10 ng/25 ng for morphine and 5 ng/10 ng for codeine. This method was applied to the analysis of six brain areas (hippocampus, frontal lobe, occipital lobe, nuclei, bulb and pons) coming from two cases of heroin-r…
Task relevance and recognition of concealed information have different influences on electrodermal activity and event-related brain potentials.
2009
This study aimed at differentiating between memory- and task-related processes and their correlates on the electrodermal and electrocortical level during information concealment. Variations of the Guilty Knowledge Test were implemented in two experiments while we measured skin conductance responses (SCRs) and event-related brain potentials. P300 amplitudes were specifically enhanced for items requiring a deviant behavioral response but they were not sensitive to concealed knowledge. In contrast, N200 amplitudes differed between memorized and irrelevant items in both experiments. SCR measures reflected a combined influence of task relevance and probe recognition, and they provided incrementa…
An approach to single trial analysis of event-related potentials based on signal detection theory.
1996
Abstract The aim of the present paper was to introduce a single trial analysis to event-related potential measurement in order to illuminate the mechanisms behind an impaired P300 amplitude occurring under certain experimental conditions. For this purpose we applied tools from linear system theory and signal detection theory to single trials in an oddball paradigm in order to estimate the amplitude of the positive deflection around the P300 latency following target and nontarget stimuli. According to the density functions of these amplitude distributions we operationally defined ‘P300 absent in target’ (P300 amplitude smaller than an individual threshold under target conditions) as well as …