948 resultados para non invasive sampling


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Extracorporeal shock waves are defined as a sequence of sonic pulses characterized by high peak pressure over 100 MPa, fast pressure rise, and short lifecycle. In the 1980s extracorporeal shock wave lithotripsy (ESWL) was first used for the treatment of urolithiasis. Orthopedic surgeons use extracorporeal shock wave therapy (ESWT) to treat non-union fractures, tendinopathies and osteonecrosis. The first application of ESWT in dermatology was for recalcitrant skin ulcers. Several studies in the last 10 years have shown that ESWT promotes angiogenesis, increases perfusion in ischemic tissues, decreases inflammation, enhances cell differentiation and accelerates wound healing. We successfully treated a non-healing chronic venous leg ulcer with ESWT. Furthermore we observed an improvement of the lymphatic drainage after application of ESWT. We are confident that ESWT is a non-invasive, practical, safe and efficient physical treatment modality for recalcitrant leg ulcers.

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BACKGROUND AND OBJECTIVE Phenotyping cocktails use a combination of cytochrome P450 (CYP)-specific probe drugs to simultaneously assess the activity of different CYP isoforms. To improve the clinical applicability of CYP phenotyping, the main objectives of this study were to develop a new cocktail based on probe drugs that are widely used in clinical practice and to test whether alternative sampling methods such as collection of dried blood spots (DBS) or saliva could be used to simplify the sampling process. METHODS In a randomized crossover study, a new combination of commercially available probe drugs (the Basel cocktail) was tested for simultaneous phenotyping of CYP1A2, CYP2B6, CYP2C9, CYP2C19, CYP2D6 and CYP3A4. Sixteen subjects received low doses of caffeine, efavirenz, losartan, omeprazole, metoprolol and midazolam in different combinations. All subjects were genotyped, and full pharmacokinetic profiles of the probe drugs and their main metabolites were determined in plasma, dried blood spots and saliva samples. RESULTS The Basel cocktail was well tolerated, and bioequivalence tests showed no evidence of mutual interactions between the probe drugs. In plasma, single timepoint metabolic ratios at 2 h (for CYP2C19 and CYP3A4) or at 8 h (for the other isoforms) after dosing showed high correlations with corresponding area under the concentration-time curve (AUC) ratios (AUC0-24h parent/AUC0-24h metabolite) and are proposed as simple phenotyping metrics. Metabolic ratios in dried blood spots (for CYP1A2 and CYP2C19) or in saliva samples (for CYP1A2) were comparable to plasma ratios and offer the option of minimally invasive or non-invasive phenotyping of these isoforms. CONCLUSIONS This new combination of phenotyping probe drugs can be used without mutual interactions. The proposed sampling timepoints have the potential to facilitate clinical application of phenotyping but require further validation in conditions of altered CYP activity. The use of DBS or saliva samples seems feasible for phenotyping of the selected CYP isoforms.

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Stable coronary artery disease is the most common clinical manifestation of ischaemic heart disease and a leading cause of mortality worldwide. Myocardial revascularisation is a mainstay in the treatment of symptomatic patients or those with ischaemia-producing coronary lesions, and reduces ischaemia to a greater extent than medical treatment. Documentation of ischaemia and plaque burden is fundamental in the risk stratification of patients with stable coronary artery disease, and several invasive and non-invasive techniques are available (eg, fractional flow reserve or intravascular ultrasound) or being validated (eg, instantaneous wave-free ratio and optical coherence tomography). The use of new-generation drug-eluting stents and arterial conduits greatly improve clinical outcome in patients undergoing percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG). PCI is feasible, safe, and effective in many patients with stable coronary artery disease who remain symptomatic despite medical treatment. In patients with multivessel and left main coronary artery disease, the decision between PCI or CABG is guided by the local Heart Team (team of different cardiovascular specialists, including non-invasive and invasive cardiologists, and cardiac surgeons), who carefully judge the possible benefits and risks inherent to PCI and CABG. In specific subsets, such as patients with diabetes and advanced, multivessel coronary artery disease, CABG remains the standard of care in view of improved protection against recurrent ischaemic adverse events.

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UNLABELLED Evidence for target values of arterial oxygen saturation (SaO2), CO2, and pH has changed substantially over the last 20 years. A representative survey concerning treatment strategies in extremely low-birth-weight infants (ELBW) was sent to all German neonatal intensive care units (NICUs) treating ELBW infants in 1997. A follow-up survey was conducted in 2011 and sent to all NICUs in Germany, Austria, and Switzerland. During the observation period, NICUs targeting SaO2 of 80, 85, and 90 % have increased, while units aiming for 94 and 96 % decreased (all p < 0.001). Similarly, NICUs aiming for pH 7.25 or lower increased, while 7.35 or higher decreased (both p < 0.001). Furthermore, more units targeted a CO2 of 50 mmHg (7.3 kPa) or higher (p < 0.001), while fewer targeted 40 or 35 mmHg (p < 0.001). Non-invasive ventilation (NIV) was used in 80.2 % of NICUs in 2011. The most frequently used ventilation modes were synchronized intermittent mandatory ventilation (SIMV) (67.5 %) and intermittent positive pressure ventilation (IPPV) (59.7 %) in 1997 and SIMV (77.2 %) and synchronized intermittent positive pressure ventilation (SIPPV) (26.8 %) in 2011. NICUs reporting frequent or always use of IPPV decreased to 11.0 % (p < 0.001). SIMV (77.2 %) and SIPPV (26.8 %) did not change from 1997 to 2011, while high-frequency oscillation (HFO) increased from 9.1 to 19.7 % (p = 0.018). Differences between countries, level of care, and size of the NICU were minimal. CONCLUSIONS Target values for SaO2 decreased, while CO2 and pH increased significantly during the observation period. Current values largely reflect available evidence at time of the surveys. WHAT IS KNOWN • Evidence concerning target values of oxygen saturation, CO 2 , and pH in extremely low-birth-weight infants has grown substantially. • It is not known to which extent this knowledge is transferred into clinical practice and if treatment strategies have changed. WHAT IS NEW • Target values for oxygen saturation in ELBW infants decreased between 1997 and 2011 while target values for CO 2 and pH increased. • Similar treatment strategies existed in different countries, hospitals of different size, or university versus nonuniversity hospitals in 2011.

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Dynamic contrast agent-enhanced magnetic resonance imaging (DCE MRI) data, when analyzed with the appropriate pharmacokinetic models, have been shown to provide quantitative estimates of microvascular parameters important in characterizing the angiogenic activity of malignant tissue. These parameters consist of the whole blood volume per unit volume of tissue, v b, transport constant from the plasma to the extravascular, extracellular space (EES), k1 and the transport constant from the EES to the plasma, k2. Parameters vb and k1 are expected to correlate with microvascular density (MVD) and vascular permeability, respectively, which have been suggested to serve as surrogate markers for angiogenesis. In addition to being a marker for angiogenesis, vascular permeability is also useful in estimating tumor penetration potential of chemotherapeutic agents. ^ Histological measurements of the intratumoral microvascular environment are limited by their invasiveness and susceptibility to sampling errors. Also, MVD and vascular permeability, while useful for characterizing tumors at a single time point, have shown less utility in longitudinal studies, particularly when used to monitor the efficacy of antiangiogenic and traditional chemotherapeutic agents. These limitations led to a search for a non-invasive means of characterizing the microvascular environment of an entire tumor. ^ The overall goal of this project was to determine the utility of DCE MRI for monitoring the effect of antiangiogenic agents. Further applications of a validated DCE MRI technique include in vivo measurements of tumor microvascular characteristics to aid in determining prognosis at presentation and in estimating drug penetration. DCE MRI data were generated using single- and dual-tracer pharmacokinetic models with different molecular-weight contrast agents. The resulting pharmacokinetic parameters were compared to immunohistochemical measurements. The model and contrast agent combination yielding the best correlation between the pharmacokinetic parameters and histological measures was further evaluated in a longitudinal study to evaluate the efficacy of DCE MRI in monitoring the intratumoral microvascular environment following antiangiogenic treatment. ^

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To demonstrate the ability to assess long-term hypothalamic-pituitary-adrenocortical (HPA) axis activity in polar bears (Ursus maritimus), a pilot study was conducted in which cortisol concentration was analyzed in hair from 7 female (3-19 years) and 10 male (6-19 years) East Greenland polar bears sampled in 1994-2006. The hair was chosen as matrix as it is non-invasive, seasonally harmonized, and has been validated as an index of long-term changes in cortisol levels. The samples were categorized according to contamination: eight were clean (2 females, 6 males), 5 had been contaminated with bear blood (2 F, 3 M), and 4 with bear fat (3 F, 1 M). There was no significant difference in cortisol concentration between the three categories after external contamination was removed. However, contaminated hair samples should be cleaned before cortisol determination. Average hair cortisol concentration was 8.90 pg/mg (range: 5.5 to 16.4 pg/mg). There was no significant correlation between cortisol concentration and age (p = 0.81) or sampling year (p = 0.11). However, females had higher mean cortisol concentration than males (females mean: 11.0 pg/mg, males: 7.3 pg/mg; p = 0.01). The study showed that polar bear hair contains measurable amounts of cortisol and that cortisol in hair may be used in studies of long-term stress in polar bears.

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In the last decade, the aquatic eddy correlation (EC) technique has proven to be a powerful approach for non-invasive measurements of oxygen fluxes across the sediment water interface. Fundamental to the EC approach is the correlation of turbulent velocity and oxygen concentration fluctuations measured with high frequencies in the same sampling volume. Oxygen concentrations are commonly measured with fast responding electrochemical microsensors. However, due to their own oxygen consumption, electrochemical microsensors are sensitive to changes of the diffusive boundary layer surrounding the probe and thus to changes in the ambient flow velocity. The so-called stirring sensitivity of microsensors constitutes an inherent correlation of flow velocity and oxygen sensing and thus an artificial flux which can confound the benthic flux determination. To assess the artificial flux we measured the correlation between the turbulent flow velocity and the signal of oxygen microsensors in a sealed annular flume without any oxygen sinks and sources. Experiments revealed significant correlations, even for sensors designed to have low stirring sensitivities of ~0.7%. The artificial fluxes depended on ambient flow conditions and, counter intuitively, increased at higher velocities because of the nonlinear contribution of turbulent velocity fluctuations. The measured artificial fluxes ranged from 2 - 70 mmol m**-2 d**-1 for weak and very strong turbulent flow, respectively. Further, the stirring sensitivity depended on the sensor orientation towards the flow. Optical microsensors (optodes) that should not exhibit a stirring sensitivity were tested in parallel and did not show any significant correlation between O2 signals and turbulent flow. In conclusion, EC data obtained with electrochemical sensors can be affected by artificial flux and we recommend using optical microsensors in future EC-studies. Flume experiments were conducted in February 2013 at the Institute for Environmental Sciences, University of Koblenz-Landau Landau. Experiments were performed in a closed oval-shaped acrylic glass flume with cross-sectional width of 4 cm and height of 10 cm and total length of 54 cm. The fluid flow was induced by a propeller driven by a motor and mean flow velocities of up to 20 cm s-1 were generated by applying voltages between 0 V and 4 V DC. The flume was completely sealed with an acrylic glass cover. Oxygen sensors were inserted through rubber seal fittings and allowed positioning the sensors with inclinations to the main flow direction of ~60°, ~95° and ~135°. A Clark type electrochemical O2 microsensor with a low stirring sensitivity (0.7%) was tested and a fast-responding needle-type O2 optode (PyroScience GmbH, Germany) was used as reference as optodes should not be stirring sensitive. Instantaneous three-dimensional flow velocities were measured at 7.4 Hz using stereoscopic particle image velocimetry (PIV). The velocity at the sensor tip was extracted. The correlation of the fluctuating O2 sensor signals and the fluctuating velocities was quantified with a cross-correlation analysis. A significant cross-correlation is equivalent to a significant artificial flux. For a total of 18 experiments the flow velocity was adjusted between 1.7 and 19.2 cm s**-1, and 3 different orientations of the electrochemical sensor were tested with inclination angles of ~60°, ~95° and ~135° with respect to the main flow direction. In experiments 16-18, wavelike flow was induced, whereas in all other experiments the motor was driven by constant voltages. In 7 experiments, O2 was additionally measured by optodes. Although performed simultaneously with the electrochemical sensor, optode measurements are listed as separate experiments (denoted by the attached 'op' in the filename), because the velocity time series was extracted at the optode tip, located at a different position in the flume.

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Increasing attention is being paid to the possible development of non-invasive tests for the assessment of the quality of fruits We propose a novel non-destructive method for the measurement of the internal optical properties of fruits and vegetables by means of time resolved reflectance spectroscopy in the visible and NIR range. A fully automated instrumentation for time-resolved reflectance measurements was developed It is based on mode-locked laser sources and electronics for time-correlated single photon counting, and provides a time-resolution of 120-160 ps The system was used to probe the optical properties of several species and varieties of fruits and vegetables in the red and NIR range (650-1000 nm). In most fruits, the absorption line shape is dominated by the absorption peak of water, centred around 970 nm Generally, the absorption spectra also show the spectral features typical of chlorophyll, with maximum at 675 nm In particular, for what concerns apples, variations in peak intensity are observed depending on the variety, the degree of ripeness as well as the position on the apple. For all the species and varieties considered, the transport scattering coefficient decreases progressively upon increasing the wavelength.

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Increasing attention is being paid to the possible development of non-invasive tests for the assessment of the quality of Fruits. We propose a novel non-destructive method for the measurement of the internal optical properties of fruits and vegetables by means of lime-resolved reflectance spectroscopy in the visible and NIR range. A Fully automated instrumentation for time-resolved reflectance measurements was developed. It is based on mode-locked laser sources and electronics for time-correlated single photon counting, and provides a time-resolution of 120-160 ps. The system was used to probe the optical properties of several species and varieties of Fruits and vegetables in the red and NIR range (650-1000 nm). In most Fruits, the absorption line shape is dominated by the absorption peak of water, centred around 970 nm. Generally, the absorption spectra also show the spectral features typical of chlorophyll, with maximum at 675 nm. In particular, for what concerns apples, variations in peak intensity are observed depending on the variety, the degree of ripeness as well as the position on the apple. For all the species and varieties considered, the transport scattering coefficient decreases progressively upon increasing the wavelength.

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Apples can be considered as having a complex system formed by several structures at different organization levels: macroscale (mayor que100 ?m) and microscale (menor que100 ?m). This work implements 2D T1/T2 global and localized relaxometry sequences on whole apples to be able to perform an intensive non-destructive and non-invasive microstructure study. The 2D T1/T2 cross-correlation spectroscopy allows the extraction of quantitative information about the water compartmentation in different subcellular organelles. A clear difference is found as sound apples show neat peaks for water in different subcellular compartments, such as vacuolar, cytoplasmatic and extracellular water, while in watercore-affected tissues such compartments appear merged. Localized relaxometry allows for the predefinition of slices in order to understand the microstructure of a particular region of the fruit, providing information that cannot be derived from global 2D T1/T2 relaxometry.

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Apples can be considered as having a complex system formed by several structures at different organization levels: macroscale (>100 μm) and microscale (<100 μm). This work implements 2D T1/T2 global and localized relaxometry sequences on whole apples to be able to perform an intensive non-destructive and non-invasive microstructure study. The 2D T1/T2 cross-correlation spectroscopy allows the extraction of quantitative information about the water compartmentation in different subcellular organelles. A clear difference is found as sound apples show neat peaks for water in different subcellular compartments, such as vacuolar, cytoplasmatic and extracellular water, while in watercore-affected tissues such compartments appear merged. Localized relaxometry allows for the predefinition of slices in order to understand the microstructure of a particular region of the fruit, providing information that cannot be derived from global 2D T1/T2 relaxometry.

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Understanding arterial distensibility has shown to be important in the pathogenesis of cardiovascular abnormalities like hypertension. It is also known that arterial pulse wave velocity (PWV) is a measure of the elasticity or stiffness of peripheral arterial blood vessels. However, it generally requires complex instrumentations to have an accurate measurement and not suited for continual monitoring. In this paper, it describes a simple and non-intrusive method to detect the cardiovascular pulse from a human wrist above the radial artery and a fingertip. The main components of this proposed method are a piezoelectric transducer and a photo-plethysmography circuitry. 5 healthy adults (4 male) with age ranging from 25 to 38 years were recruited. The timing consistency of the detected pulsations is first evaluated and compared to that obtained from a commercial electrocardiogram. Furthermore, the derived PWV is then assessed by the predicted values attained from regression equations of two previous similar studies. The results show good correlations (p < 0.05) and similarities for the former and latter respectively. The simplicity and non-invasive nature of the proposed method can be attractive for even younger or badly disturbed patients. Moreover, it can be used for prolonged monitoring for the comfort of the patients.

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One of the most pressing demands on electrophysiology applied to the diagnosis of epilepsy is the non-invasive localization of the neuronal generators responsible for brain electrical and magnetic fields (the so-called inverse problem). These neuronal generators produce primary currents in the brain, which together with passive currents give rise to the EEG signal. Unfortunately, the signal we measure on the scalp surface doesn't directly indicate the location of the active neuronal assemblies. This is the expression of the ambiguity of the underlying static electromagnetic inverse problem, partly due to the relatively limited number of independent measures available. A given electric potential distribution recorded at the scalp can be explained by the activity of infinite different configurations of intracranial sources. In contrast, the forward problem, which consists of computing the potential field at the scalp from known source locations and strengths with known geometry and conductivity properties of the brain and its layers (CSF/meninges, skin and skull), i.e. the head model, has a unique solution. The head models vary from the computationally simpler spherical models (three or four concentric spheres) to the realistic models based on the segmentation of anatomical images obtained using magnetic resonance imaging (MRI). Realistic models – computationally intensive and difficult to implement – can separate different tissues of the head and account for the convoluted geometry of the brain and the significant inter-individual variability. In real-life applications, if the assumptions of the statistical, anatomical or functional properties of the signal and the volume in which it is generated are meaningful, a true three-dimensional tomographic representation of sources of brain electrical activity is possible in spite of the ‘ill-posed’ nature of the inverse problem (Michel et al., 2004). The techniques used to achieve this are now referred to as electrical source imaging (ESI) or magnetic source imaging (MSI). The first issue to influence reconstruction accuracy is spatial sampling, i.e. the number of EEG electrodes. It has been shown that this relationship is not linear, reaching a plateau at about 128 electrodes, provided spatial distribution is uniform. The second factor is related to the different properties of the source localization strategies used with respect to the hypothesized source configuration.

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Establishing an association between the scent a perpetrator left at a crime scene to the odor of the suspect of that crime is the basis for the use of human scent identification evidence in a court of law. Law enforcement agencies gather evidence through the collection of scent from the objects that a perpetrator may have handled during the execution of the criminal act. The collected scent evidence is consequently presented to the canines for identification line-up procedures with the apprehended suspects. Presently, canine scent identification is admitted as expert witness testimony, however, the accurate behavior of the dogs and the scent collection methods used are often challenged by the court system. The primary focus of this research project entailed an evaluation of contact and non-contact scent collection techniques with an emphasis on the optimization of collection materials of different fiber chemistries to evaluate the chemical odor profiles obtained using varying environment conditions to provide a better scientific understanding of human scent as a discriminative tool in the identification of suspects. The collection of hand odor from female and male subjects through both contact and non-contact sampling approaches yielded new insights into the types of VOCs collected when different materials are utilized, which had never been instrumentally performed. Furthermore, the collected scent mass was shown to be obtained in the highest amounts for both gender hand odor samples on cotton sorbent materials. Compared to non-contact sampling, the contact sampling methods yielded a higher number of volatiles, an enhancement of up to 3 times, as well as a higher scent mass than non-contact methods by more than an order of magnitude. The evaluation of the STU-100 as a non-contact methodology highlighted strong instrumental drawbacks that need to be targeted for enhanced scientific validation of current field practices. These results demonstrated that an individual's human scent components vary considerably depending on the method used to collect scent from the same body region. This study demonstrated the importance of collection medium selection as well as the collection method employed in providing a reproducible human scent sample that can be used to differentiate individuals.

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Background and Objectives: The measurement of salivary immunoglobulin A is a useful and non-invasive method for measuring stress. Personality traits and rumination act as possible mediators in the relationship between psychological stressors and the immune system. This study was aimed to evaluate the levels of salivary IgA under psychological stress and its relationship with rumination and five personality traits in medical students. Methods: In this cross- sectional study, 45 medical students who intended to participate in the final exam were selected by simple random sampling. Two months before the exam, in the basal conditions, the NEO Personality Inventory-Short Form and Emotional Control Questionnaire (ECQ) were completed. Saliva samples were taken from students in both the basal conditions and exam stress conditions. Salivary IgA was measured by an ELISA test. Data was analyzed using paired samples T-test, Pearson correlation analysis, and stepwise regression. Results: A significant reduction of salivary IgA levels was found in exam stress conditions. Also, a significant negative correlation was found between traits of neuroticism and rumination with salivary IgA, as well as a significant positive correlation between of openness to experience and emotional inhibition with salivary IgA. Openness to experience and emotional inhibition may predict a substantial variance (34%) of salivary IgA under exam stress. Conclusions: Salivary IgA is reduced in response to exam stress. In addition, the rumination and personality traits may reduce or increase stress effects on the immune system, particularly the salivary IgA.