Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 321
Filter
Add more filters

Publication year range
1.
Prostaglandins Other Lipid Mediat ; 162: 106660, 2022 10.
Article in English | MEDLINE | ID: mdl-35714920

ABSTRACT

Prostanoids are potent lipid mediators involved in a wide variety of physiological functions like blood pressure regulation or inflammation as well as cardiovascular and malign diseases. Elucidation of their modes of action is mainly carried out in pre-clinical animal models by quantifying prostanoids in tissues of interest. Unfortunately, prostanoids are prone to post-mortem artifact formation and de novo synthesis can already be caused by external stimuli during the euthanasia of animals like prolonged hypercapnia or ischemia. Therefore, this study investigates the suitability and impact of fast cervical dislocation for the determination of prostanoids (6-keto-PGF1α, TXB2, PGF2α, PGD2, PGE2) in seven tissues of mice (spinal cord, brain, sciatic nerve, kidney, liver, lung, and spleen) to minimize time-dependent effects and approximate physiological concentrations. Tissues were dissected in a standardized sequence directly or after 10 min to investigate the influence of dissection delays. The enzyme inhibitor indomethacin (10 µM) in combination with low processing temperatures was employed to preserve prostanoid concentrations during sample preparation. Quantification of prostanoids was performed via LC-MS/MS. This study shows, that prostanoids are differentially susceptible to post-mortem artifact formation which is closely connected to their physiological function and metabolic stability in the respective tissues. Prostanoids in the brain, spinal cord, and kidney that are not involved in the regulatory response post-mortem, i.e. blood flow regulation (6-keto-PGF1α, PGE2, PGF2α) showed high reproducibility even after dissection delay and could be assessed after fast cervical dislocation if prerequisites like standardized pre-analytical workflows with immediate dissection and inhibition of residual enzymatic activity are in place. However, in tissues with high metabolic activity (liver, lung) more stable prostanoid metabolites should be used. Moreover, prostanoids in the spleen were strongly affected by dissection delays and presumably the method of euthanasia itself.


Subject(s)
Prostaglandins , Tandem Mass Spectrometry , Animals , Chromatography, Liquid , Dinoprostone , Indomethacin/pharmacology , Mice , Prostaglandins/metabolism , Prostaglandins E , Prostaglandins F , Reproducibility of Results , Tandem Mass Spectrometry/methods
2.
Br J Anaesth ; 121(3): 647-655, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30115263

ABSTRACT

BACKGROUND: The paediatric preoperative fasting time of 2 h for clear fluids, as suggested by guidelines, is often exceeded. Shorter preoperative fasting has been proposed to avoid potential outcomes such as dehydration, ketoacidosis, reduced arterial blood pressure, and patient discomfort. The aim of this study was to investigate whether liberal clear fluid intake until premedication significantly reduces actual fasting time and impacts gastric pH and residual volume. METHODS: Children (1-16 yr old, ASA I or II) undergoing elective procedures with general anaesthesia requiring tracheal intubation were randomised for clear fluid intake until premedication with midazolam (liberal) or 2 h fluid fasting (standard). Actual fasting times were recorded. Gastric content was sampled after tracheal intubation with an orogastric tube to determine gastric pH and residual volume. Data are presented as median [interquartile range]. RESULTS: We included 162 children aged 1.1-16 yr; gastric pH was determined in 138 patients. Patients' characteristics were similar in the two groups. The liberal fasting group had significantly shorter fasting times (48 [18.5-77.5] vs 234 [223.5-458.5] min; P<0.001). No significant difference was observed regarding gastric pH (1.6 [1.5-1.8] vs 1.6 [1.4-1.7]; P=0.237) or residual volume (0.38 [0.1-1.1] vs 0.43 [0.13-0.73] ml kg-1; P=0.535). Twelve patients (15%) in the liberal group (median fluid fasting 32 min) vs one patient (1%) had gastric residual volumes >2 ml kg-1 (P=0.001). CONCLUSION: Fluid intake until premedication allows for significantly shorter fasting times. Elevated gastric residual volumes may occur more often in patients with fasting times of 30 min or shorter. CLINICAL TRIAL REGISTRATION: NCT02603094.


Subject(s)
Anesthesia, General/methods , Drinking/physiology , Fasting/physiology , Preoperative Care/methods , Adolescent , Child , Child, Preschool , Elective Surgical Procedures , Female , Gastric Acidity Determination , Gastric Juice/metabolism , Gastrointestinal Contents , Humans , Hydrogen-Ion Concentration , Infant , Intubation, Intratracheal , Male , Premedication , Preoperative Period
3.
Nature ; 481(7381): 344-7, 2012 Jan 18.
Article in English | MEDLINE | ID: mdl-22258613

ABSTRACT

Silicon is more than the dominant material in the conventional microelectronics industry: it also has potential as a host material for emerging quantum information technologies. Standard fabrication techniques already allow the isolation of single electron spins in silicon transistor-like devices. Although this is also possible in other materials, silicon-based systems have the advantage of interacting more weakly with nuclear spins. Reducing such interactions is important for the control of spin quantum bits because nuclear fluctuations limit quantum phase coherence, as seen in recent experiments in GaAs-based quantum dots. Advances in reducing nuclear decoherence effects by means of complex control still result in coherence times much shorter than those seen in experiments on large ensembles of impurity-bound electrons in bulk silicon crystals. Here we report coherent control of electron spins in two coupled quantum dots in an undoped Si/SiGe heterostructure and show that this system has a nuclei-induced dephasing time of 360 nanoseconds, which is an increase by nearly two orders of magnitude over similar measurements in GaAs-based quantum dots. The degree of phase coherence observed, combined with fast, gated electrical initialization, read-out and control, should motivate future development of silicon-based quantum information processors.

4.
Acta Anaesthesiol Scand ; 62(10): 1389-1395, 2018 11.
Article in English | MEDLINE | ID: mdl-29943477

ABSTRACT

BACKGROUND: Paediatric emergency tapes provide drug dosing based on the patient's estimated body weight. Unfortunately, published data revealed an unsatisfactory accuracy. A newly developed digital algorithm for weight estimation (CLAWAR) allowing a three-staged habitus adaptation (normal, obese, or cachectic; CLAWAR-3) demonstrated a higher accuracy for weight estimation compared to paediatric emergency tapes. However, the incidence of incorrectly evaluated habitus was 27%. A five-staged habitus adaptation with figural images was suggested by Wells et al to improve habitus and weight estimation. Therefore, CLAWAR was modified with five habitus stages including figural images (CLAWAR-5). We hypothized CLAWAR-5 improves the accuracy of weight estimation. METHODS: After obtaining informed written parental consent patients were included in this single centre, prospective clinical observation trial. Body weight estimations by CLAWAR-3 and CLAWAR-5 within ±10% of the actual body weight were compared. Furthermore, the incidence of correct evaluated habitus was calculated. McNemar Tests were used for statistical analysis. Results presented as median (interquartiles), P < .003 considered significant. RESULTS: In total, 312 patients aged 3.3 years (0.7-6.6), with a body length of 95.9 cm (70.0-121.2), weighing 14.8 kg (8.1-22.5), were included. Both CLAWAR-3 and CLAWAR-5 showed equivalent accuracy for weight estimation within the ±10% interval (62.2% vs 60.6%, P = .609). Despite adding figural images, the incidence of correct evaluated habitus with CLAWAR-5 (46.8%) was worse than with CLAWAR-3 (66.7%). CONCLUSION: The five-staged habitus-adapted method could not improve the accuracy of weight estimation. Furthermore, the error rate of habitus classification was not reduced by the implementation of figural images.


Subject(s)
Body Height , Body Mass Index , Body Weight , Child , Child, Preschool , Female , Humans , Infant , Male , Prospective Studies
5.
J Public Health (Oxf) ; 40(3): e235-e243, 2018 09 01.
Article in English | MEDLINE | ID: mdl-29294096

ABSTRACT

Background: Whereas the association between education and health in later life is well described, investigations about the underlying mechanisms of these health inequalities are scarce. This study examines the relative contribution of material, behavioral and psychosocial factors to health inequalities in older Germans. Methods: Data were drawn from the fifth wave of the Survey of Health, Ageing and Retirement in Europe (SHARE). The analytic sample included 3246 participants aged 60-85 years. We examined the independent and indirect contribution of material, behavioral and psychosocial factors to the association between education and self-rated health based on logistic regression models. Results: Material factors were most important as they were additionally working through behavioral and psychosocial factors whereas the independent contribution of behavioral and psychosocial factors was much lower than suggested in the separate analyses of the three explanatory pathways. Conclusions: Policy interventions that focus on the improvement of material living conditions might reduce health inequalities in old age. In studies on the underlying mechanisms of health inequalities, material, behavioral and psychosocial factors should be modeled as inter-related predictors as the separate analysis does not reveal their actual contribution so that the relevance of single explanatory pathways might be overestimated.


Subject(s)
Health Status Disparities , Aged , Aged, 80 and over , Educational Status , Female , Germany/epidemiology , Health Behavior , Humans , Male , Middle Aged , Psychology , Risk Factors , Social Determinants of Health/statistics & numerical data , Socioeconomic Factors
6.
Acta Anaesthesiol Scand ; 61(9): 1122-1132, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28791696

ABSTRACT

BACKGROUND: Emergency tapes like the "Paediatric-Emergency-Ruler" (PaedER) provide drug dosing and recommend medical airway equipment based on estimated patient bodyweight and age. Previous studies have revealed unsatisfactory accuracy in bodyweight estimation, due to the tapes' length-based weight categories. Therefore, we developed a digital algorithm allowing continuous length-based estimation of weight and age. The aim of this study was to compare the new algorithm with the PaedER regarding accuracy in estimating bodyweight and recommendation of medical airway equipment. METHODS: Patients with a body length suitable for the PaedER were included in this single centre, prospective clinical observation trial after obtaining informed written parental consent. Bodyweight estimations by the algorithm and PaedER within ± 10% and ± 20% of the actual bodyweight were compared. Furthermore, medical airway equipment suggested by the PaedER and algorithm were compared with the equipment actually used for anaesthesia. Wilcoxon- and McNemar-Tests were used for statistical analysis. Results are median (interquartiles), P < 0.05 was considered significant. RESULTS: In total, 489 patients aged 2.0 years (0.4-5.9), with a body length of 89.0 cm (63.5-114.5), weighing 12.8 kg (6.3-19.6), were included. The algorithm's precision of bodyweight estimation within ± 10%/± 20% was significantly higher at 64.0%/91.6% than the PaedER at 55.4%/81.8% (P < 0.001). Compared to PaedER the algorithm showed a higher incidence of correctly recommended medical airway equipment based on its accuracy for age and bodyweight estimation. CONCLUSION: The new digital algorithm is an alternative to conventional emergency tapes, showing improved accuracy regarding length-based estimation of bodyweight and recommendation of medical airway equipment.


Subject(s)
Algorithms , Body Weight , Emergency Medical Services/methods , Age Factors , Airway Management/methods , Anesthesia/methods , Body Height , Child, Preschool , Female , Humans , Infant , Male , Prospective Studies , Reproducibility of Results
7.
Acta Anaesthesiol Scand ; 61(8): 895-903, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28685824

ABSTRACT

BACKGROUND: Hospitalization, surgery and anaesthesia may lead to new-onset maladaptive behaviour, emotional distress and trauma. This pilot study aims to investigate the influence of intraoperatively applied music on post-operative behaviour in children and adolescents. METHODS: Children with an ASA physical state classification of I or II, aged from 4 to 16 years and scheduled for elective circumcision or inguinal hernia repair under combined general and caudal anaesthesia were included. The children were randomized into two groups. They wore headphones during surgery, and were either exposed to music or not. All involved staff were blinded. Post-operative behaviour was documented by parents on day 7, 14 and 28 after surgery, using a questionnaire adapted from the "Post Hospitalization Behavioural Questionnaire" (PHBQ). Overall occurrence of at least one item indicating maladaptive behaviour was the primary outcome. Data are presented as median (interquartile range). RESULTS: In total, 135 children aged 6.6 (5.3-8.5) years, weighing 22 (19-29) kg, were included, with 112 completed questionnaires returned. Overall occurrence of at least one maladaptive item was lower in the music group, with a significantly lower incidence on day 7 (51% vs. 77% in controls; P < 0.01). CONCLUSION: Intraoperative music application in children undergoing minor surgical procedures may reduce the incidence of post-operative maladaptive behaviour within the first week.


Subject(s)
Intraoperative Care/methods , Music/psychology , Adolescent , Anesthesia, Caudal , Anesthesia, General , Child , Child Behavior Disorders/prevention & control , Child Behavior Disorders/psychology , Child, Preschool , Double-Blind Method , Female , Hernia, Inguinal/surgery , Humans , Male , Pilot Projects , Postoperative Complications/prevention & control , Postoperative Complications/psychology , Postoperative Period , Prospective Studies
8.
Anaesthesia ; 72(11): 1357-1364, 2017 Nov.
Article in English | MEDLINE | ID: mdl-28695980

ABSTRACT

Capnography (ETCO2 ) is routinely used as a non-invasive estimate of arterial carbon dioxide (PaCO2 ) levels in order to modify ventilatory settings, whereby it is assumed that there is a positive gap between PaCO2 and ETCO2 of approximately 0.5 kPa. However, negative values (ETCO2 > PaCO2 ) can be observed. We retrospectively analysed arterial to end-tidal carbon dioxide differences in 799 children undergoing general anaesthesia with mechanical ventilation of the lungs in order to elucidate predictors for a negative gap. A total of 2452 blood gas analysis readings with complete vital sign monitoring, anaesthesia gas analysis and spirometry data were analysed. Mean arterial to end-tidal carbon dioxide difference was -0.18 kPa (limits of 95% agreement -1.10 to 0.74) and 71.2% of samples demonstrated negative values. The intercept model revealed PaCO2 to be the strongest predictor for a negative PaCO2 -ETCO2 difference. A decrease in PaCO2 by 1 kPa resulted in a decrease in the PaCO2 -ETCO2 difference by 0.23 kPa. This study demonstrates that ETCO2 monitoring in children whose lungs are mechanically ventilated may paradoxically lead to overestimation of ETCO2 (ETCO2 > PaCO2 ) with a subsequent risk of unrecognised hypocarbia.


Subject(s)
Anesthesia, General , Carbon Dioxide/analysis , Respiration, Artificial , Adolescent , Blood Gas Analysis , Capnography , Catheters, Indwelling , Child , Child, Preschool , Female , Humans , Infant , Male , Monitoring, Intraoperative , Retrospective Studies , Spirometry
9.
Phys Rev Lett ; 116(11): 110402, 2016 Mar 18.
Article in English | MEDLINE | ID: mdl-27035289

ABSTRACT

We demonstrate improved operation of exchange-coupled semiconductor quantum dots by substantially reducing the sensitivity of exchange operations to charge noise. The method involves biasing a double dot symmetrically between the charge-state anticrossings, where the derivative of the exchange energy with respect to gate voltages is minimized. Exchange remains highly tunable by adjusting the tunnel coupling. We find that this method reduces the dephasing effect of charge noise by more than a factor of 5 in comparison to operation near a charge-state anticrossing, increasing the number of observable exchange oscillations in our qubit by a similar factor. Performance also improves with exchange rate, favoring fast quantum operations.

10.
Acta Anaesthesiol Scand ; 60(2): 241-9, 2016 Feb.
Article in English | MEDLINE | ID: mdl-26612252

ABSTRACT

BACKGROUND: The Ventrain(®) (Dolphys Medical, Eindhoven, The Netherlands) is a disposable handheld ventilation device allowing active inspiration and expiration through a transtracheal catheter. This study investigated Ventrain(®) 's performance when used with different clinical oxygen sources in an in vitro set-up. METHODS: Three anesthesia oxygen sources (wall-mounted flowmeter, respirator oxygen outlet port, and anesthesia ventilator circuit) were used at gas flow rates of 6, 9, 12, and 15 l/min. First, the sources' driving pressures (DP), the insufflation pressure (IP), and the flow at the catheter tip were measured using a gas flow analyzer. Tidal volumes (VT) delivered by the Ventrain(®) were assessed by the ASL5000 test lung (respiratory rate: 15 min(-1), I:E = 1:1, compliance: 100 ml/cmH2O, resistance: 3.06 cmH2O/l/s). RESULTS: VT ranged from 82 to 483 ml for inspiration and 82 to 419 ml for expiration. Measured IP, flow, and VT were less dependent on the set gas flow rate but more on the source's DP. With rising DP the IP, the flow at the catheter tip and consequently VT increased. At an approximate target I:E ratio of 1:1, the ratio of inspiratory to expiratory VT increased with higher DP and gas flow rates. CONCLUSION: The oxygen sources resulted in clinically different IP, flows, and VT delivered by the Ventrain(®) at given gas flow rates. This needs to be considered in a clinical emergency situation. Integrating an adjustable pressure valve into Ventrain(®) to allow regulation of the lowest necessary IP would make its use safer.


Subject(s)
Disposable Equipment , Oxygen/administration & dosage , Ventilators, Mechanical , Humans
11.
Anaesthesist ; 65(7): 514-20, 2016 Jul.
Article in German | MEDLINE | ID: mdl-27245923

ABSTRACT

BACKGROUND: The Ventrain® emergency ventilation device allows active inspiration and expiration through transtracheal catheters or the lumen of an airway exchange catheter. This single-use handheld device is manually operated and driven by an external pressurized oxygen source. The Ventrain® may be used to ventilate patients with a complete or pending upper airway obstruction reducing the risk of barotrauma due to the possibility of active expiration. However tidal volumes (V T) applied and withdrawn with the Ventrain® can only be controlled by visual inspection of chest movements; V T monitoring is not provided. Excessive inspiratory volumes or air trapping due to insufficient expiration may remain clinically undetected until pulmonary trauma and/or cardio-respiratory deterioration occur. Active expiration itself carries the risk of overwhelming lung deflation with the formation of atelectasis. Thus, an inspiratory and expiratory tidal volume monitor is urgently required. The aim of this study was to evaluate efficacy and precision of the Florian respiratory function monitor (RFM) to monitor in- and expiratory V T administered by the Ventrain® emergency ventilation device through a small cannula to the ASL 5000 test lung (ASL). METHODS: In an in-vitro setting the RFM was used with its neonatal flow sensor to monitor inspiratory and expiratory V T applied by the Ventrain® emergency ventilation device through a 2 mm internal diameter (ID) transtracheal catheter to the ASL. Driving flows of 6, 9, 12 and 15 l min(-1) were chosen to vary tidal volumes at a constant respiratory rate of 15 min(-1) and an I:E ratio of 1:1. Experiments were repeated five times with two flow sensors. An initial set-up calibration run was performed to calculate a bias correction factor for inspiratory and expiratory V T measured by the RFM. This bias correction factor was used to simulate a correction of the in the RFM programmed linearization table. In a second, identical setting the experiments were repeated five times with two flow sensors. V T measured by the adjusted RFM were compared with those obtained from the ASL 5000 in this second run and the percentage differences were calculated. Bland Altman analysis was used to investigate the agreement of inspiratory or expiratory VT measured by both methods (ASL and RFM). Calculation of the mean of differences between both methods is given as bias and the 95 % agreement interval as precision. RESULTS: Tidal volumes measured by the ASL ranged from 140 to 675 ml. The percentage correction factor was 16.27 % (2.60 %) during inspiration for V T ranged from 0 to 700 ml and 11.51 % (2.56 %) during expiration for V T of 0 to 225 ml, 7.41 % (2.94 %) for VT 226 to 325 ml and 5.35 % (3.57 %) for TV e > 325 ml. Inspiratory and expiratory tidal volumes measured by the adjusted RFM demonstrated a percentage deviation (mean [SD]) of 2.59 % (1.86 %) during inspiration and 1.66 % (1.14 %) during expiration when compared with the ASL 5000. Bias (precision) of the Bland Altman plot for the adjusted RFM is 2.05 ml (23.20) during inspiration and 4.62 ml (10.40) for expiration. CONCLUSION: The tested respiratory function monitor using hot-wire anemometer technology has the potential to monitor tidal volumes applied by the Ventrain®. With the software thus adapted, the RFM measures precise inspiratory and expiratory tidal volumes within common technical tolerance. This could help perform adequate patient ventilation with Ventrain® and reduce the potential risk of patient trauma.


Subject(s)
Emergency Medical Services/methods , Monitoring, Physiologic/instrumentation , Monitoring, Physiologic/methods , Respiration, Artificial/methods , Tidal Volume , Ventilators, Mechanical , Adult , Humans , Infant, Newborn , Patient Safety , Reproducibility of Results , Spirometry
12.
BMC Bioinformatics ; 16: 187, 2015 Jun 08.
Article in English | MEDLINE | ID: mdl-26049713

ABSTRACT

BACKGROUND: Due to the large amount of data produced by advanced microscopy, automated image analysis is crucial in modern biology. Most applications require reliable cell nuclei segmentation. However, in many biological specimens cell nuclei are densely packed and appear to touch one another in the images. Therefore, a major difficulty of three-dimensional cell nuclei segmentation is the decomposition of cell nuclei that apparently touch each other. Current methods are highly adapted to a certain biological specimen or a specific microscope. They do not ensure similarly accurate segmentation performance, i.e. their robustness for different datasets is not guaranteed. Hence, these methods require elaborate adjustments to each dataset. RESULTS: We present an advanced three-dimensional cell nuclei segmentation algorithm that is accurate and robust. Our approach combines local adaptive pre-processing with decomposition based on Lines-of-Sight (LoS) to separate apparently touching cell nuclei into approximately convex parts. We demonstrate the superior performance of our algorithm using data from different specimens recorded with different microscopes. The three-dimensional images were recorded with confocal and light sheet-based fluorescence microscopes. The specimens are an early mouse embryo and two different cellular spheroids. We compared the segmentation accuracy of our algorithm with ground truth data for the test images and results from state-of-the-art methods. The analysis shows that our method is accurate throughout all test datasets (mean F-measure: 91%) whereas the other methods each failed for at least one dataset (F-measure≤69%). Furthermore, nuclei volume measurements are improved for LoS decomposition. The state-of-the-art methods required laborious adjustments of parameter values to achieve these results. Our LoS algorithm did not require parameter value adjustments. The accurate performance was achieved with one fixed set of parameter values. CONCLUSION: We developed a novel and fully automated three-dimensional cell nuclei segmentation method incorporating LoS decomposition. LoS are easily accessible features that ensure correct splitting of apparently touching cell nuclei independent of their shape, size or intensity. Our method showed superior performance compared to state-of-the-art methods, performing accurately for a variety of test images. Hence, our LoS approach can be readily applied to quantitative evaluation in drug testing, developmental and cell biology.


Subject(s)
Algorithms , Cell Nucleus/ultrastructure , Embryo, Mammalian/ultrastructure , Imaging, Three-Dimensional/methods , Microscopy, Fluorescence/methods , Pattern Recognition, Automated , Spheroids, Cellular/ultrastructure , Animals , Breast Neoplasms/pathology , Computational Biology/methods , Female , Image Interpretation, Computer-Assisted , Mice , Pancreatic Neoplasms/pathology
13.
Magn Reson Med ; 74(6): 1803-10, 2015 Dec.
Article in English | MEDLINE | ID: mdl-25521345

ABSTRACT

PURPOSE: High-resolution MRI combined with phospholipid detection may improve breast cancer grading. Currently, configurations are optimized for either high-resolution imaging or (31) P spectroscopy. To be able to perform both imaging as well as spectroscopy in a single session, we integrated a (1) H receiver array into a (1) H-(31) P transceiver at 7T. To ensure negligible signal loss due to coupling between elements, we investigated the use of a floating decoupling loop to enable bilateral MRI and (31) P MRS. METHODS: Two quadrature double-tuned radiofrequency coils were designed for bilateral breast MR with active detuning at the (1) H frequency. The two coils were placed adjacent to each other and decoupled for both frequencies with a single resonant floating loop. Sensitivity of the bilateral configuration, facilitating space for a 26-element (1) H receive array, was compared with a transceiver configuration. RESULTS: The floating loop was able to decouple the elements over 20 dB for both frequencies. Enlargement of the elements, to provide space for the receivers, and the addition of detuning electronics altered the (31) P sensitivity by 0.4 dB. CONCLUSION: Dynamic contrast-enhanced scans of 0.7 mm isotropic, diffusion-weighted imaging, and (31) P MR spectroscopic imaging can be acquired at 7T in a single session as demonstrated in a patient with invasive ductal carcinoma.


Subject(s)
Breast Neoplasms/diagnosis , Carcinoma, Ductal, Breast/diagnosis , Diffusion Magnetic Resonance Imaging/instrumentation , Image Enhancement/instrumentation , Magnetic Resonance Spectroscopy/instrumentation , Magnetics/instrumentation , Amplifiers, Electronic , Equipment Design , Equipment Failure Analysis , Female , Humans , Molecular Imaging/methods , Phosphorus Isotopes/pharmacokinetics , Radio Waves , Radiopharmaceuticals/pharmacokinetics , Reproducibility of Results , Sensitivity and Specificity , Transducers
14.
Nanotechnology ; 26(37): 375202, 2015 Sep 18.
Article in English | MEDLINE | ID: mdl-26302871

ABSTRACT

We report on a quantum dot device design that combines the low disorder properties of undoped SiGe heterostructure materials with an overlapping gate stack in which each electrostatic gate has a dominant and unique function-control of individual quantum dot occupancies and of lateral tunneling into and between dots. Control of the tunneling rate between a dot and an electron bath is demonstrated over more than nine orders of magnitude and independently confirmed by direct measurement within the bandwidth of our amplifiers. The inter-dot tunnel coupling at the [Formula: see text] charge configuration anti-crossing is directly measured to quantify the control of a single inter-dot tunnel barrier gate. A simple exponential dependence is sufficient to describe each of these tunneling processes as a function of the controlling gate voltage.

15.
Br J Anaesth ; 114(3): 477-82, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25501720

ABSTRACT

INTRODUCTION: Current guidelines suggest a fasting time of 2 h for clear fluids, which is often exceeded in clinical practice, leading to discomfort, dehydration and stressful anaesthesia induction to patients, especially in the paediatric population. Shorter fluid fasting might be a strategy to improve patient comfort but has not been investigated yet. This prospective clinical trial compares gastric pH and residual volume after 1 vs 2 h of preoperative clear fluid fasting. METHODS: Children (1-16 yr, ASA I or II) undergoing elective procedures in general anaesthesia requiring tracheal intubation were randomized into group A with 60 min or B with 120 min preoperative clear fluid fasting. To determine gastric pH and residual volume, the gastric content was sampled in supine, left and right lateral patient position using an oro-gastric tube after intubation. Data are median (interquartile range) for group A or B (P<0.05). RESULTS: In total, 131 children aged 1.01-16.23 yr were included; gastric pH was determined in 120 cases. Patient characteristic data were similar between the two groups, except for gender (46/33 males in group A/B; P=0.02). Despite significantly shorter fasting times for clear fluids in group A compared with group B (76/136 min; P<0.001), no significant difference was observed regarding gastric pH [1.43 (1.30-1.56)/1.44 (1.29-1.68), P=0.66] or residual volume [0.43 (0.21-0.84)/0.46 (0.19-0.78) ml kg(-1), P=0.47]. CONCLUSION: One hour clear fluid fasting does not alter gastric pH or residual volume significantly compared with 2 h fasting. CLINICAL TRIAL REGISTRATION: The study was approved by the local ethics committee (KEK-ZH-Nr. 2011-0034) and registered with ClinicalTrials.gov (NCT01516775).


Subject(s)
Beverages , Fasting/metabolism , Gastric Juice/metabolism , Gastrointestinal Contents/chemistry , Preoperative Care/methods , Adolescent , Anesthesia, General , Child , Child, Preschool , Drinking , Elective Surgical Procedures , Female , Gastric Acidity Determination , Humans , Hydrogen-Ion Concentration , Infant , Male , Prospective Studies , Time Factors
16.
Anaesthesist ; 64(2): 115-21, 2015 Feb.
Article in German | MEDLINE | ID: mdl-25445813

ABSTRACT

BACKGROUND: Negative behavioral changes after anesthesia in children are common. The Post Hospitalization Behavior Questionnaire (PHBQ) was particularly developed and has been widely used in English-speaking countries to investigate such behavioral changes. The PHBQ consists of 27 questions related to behavioral features observed by parents after anesthesia or hospitalization, each involving comparison with their baseline status. AIM: A comparable diagnostic tool in German should be established. MATERIAL AND METHODS: The PHBQ was translated into German using a well defined back-translation method. A 3-point Likert scale was used to categorize behavioral features as less than, equal to or more than baseline. Overall 600 questionnaires were given out at children's hospital discharge, following surgical or medical procedures or examinations with or without concurrent anesthesia or deep sedation. After questionnaires were returned, factor and item analysis was conducted. Cronbach's alpha was calculated to determine internal consistency as a measure of reliability. RESULTS: In total, 155 returned and completed questionnaires were assessed, with patients' age ranging from 1.1 to 15.9 (median 5.7) years and length of hospitalization between 1 to 15 (median 2.5) days. The German translation of the PHBQ has a factorial structure that is similar to the English version, and its psychometric properties are also similar. After analysis of the main components and consideration of the Scree plot, either 6 or 7 factors were indicated. Analogously to the original version, we chose 6 factors, which explain 58% of variance. Items were not identically assigned to factors as with the original version, and terms used to describe the factors were slightly adapted. Reliability was adequate, with Cronbach's alpha for the 6 factors being between 0.6 and 0.82 (for total scale: Cronbach's alpha = 0.89, compared to 0.82 for the original version). Children younger than 5 years showed more negative behavioral changes than older children. There were no gender differences. CONCLUSION: With the German translation of the PHBQ presented here an instrument is available to detect negative behavioral changes after anesthesia in children among German speaking populations. The translation is comparable to the English version with minor differences concerning its factorial structure, which may be due to the predominant role of anxiety in all items. Like the original, this questionnaire does not per se discriminate between anesthesia and hospitalization induced behavioral changes. However, the German translation of the PHBQ is a questionnaire that is feasible for clinical routine and scientific settings and can be easily and quickly completed by caregivers.


Subject(s)
Adolescent Behavior , Anesthesia/adverse effects , Child Behavior Disorders/etiology , Child Behavior Disorders/psychology , Postoperative Complications/psychology , Surveys and Questionnaires , Adolescent , Child , Child, Preschool , Factor Analysis, Statistical , Female , Germany , Humans , Infant , Language , Length of Stay , Male , Reproducibility of Results
18.
J Vet Pharmacol Ther ; 37(4): 338-47, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24479850

ABSTRACT

Testosterone (TES) 6-ß-hydroxylation is a significant metabolic step in the biotransformation of TES in human liver microsomes and reflects cytochrome P450 (CYP) 3A4/5 specific metabolic activity. Several CYP3A enzymes have been annotated in the horse genome, but functional characterization is missing. This descriptive study investigates TES metabolism in the horse liver in vitro and the qualitative contribution of three CYP3A isoforms of the horse. Metabolism of TES was investigated by using equine hepatocyte primary cultures and liver microsomes. Chemical inhibitors were used to determine the CYPs involved in TES biotransformation in equine microsomes. Single CYPs 3A89, 3A94, and 3A95, recombinantly expressed in V79 hamster lung fibroblasts, were incubated with TES and the fluorescent metabolite 7-benzyloxy-4-trifluoromethylcoumarin (BFC). The effect of ketoconazole and troleandomycin was evaluated on single CYPs. Testosterone metabolites were analyzed by HPLC and confirmed by GC/MS. In hepatocyte primary cultures, the most abundant metabolite was androstenedione (AS), whereas in liver microsomes, 6-ß-hydroxytestosterone showed the largest peak. Formation of 6-ß-hydroxytestosterone and 11-ß-hydroxytestosterone in liver microsomes was inhibited by ketoconazole, troleandomycin, and quercetin. Equine recombinant CYP3A95 catalyzed 11-ß-hydroxylation of testosterone (TES). Metabolism of BFC was significantly inhibited by ketoconazole in CYP3A95, whereas troleandomycin affected the activities of CYP3A94 and CYP3A95. Both inhibitors had no significant effect on CYP3A89. Metabolic reactions and effects of inhibitors differed between the equine CYP3A isoforms investigated. This has to be considered in future in vitro studies.


Subject(s)
Cytochrome P-450 Enzyme System/metabolism , Gene Expression Regulation, Enzymologic/physiology , Horses/metabolism , Liver/metabolism , Testosterone/metabolism , Animals , Cell Line , Cricetinae , Cytochrome P-450 Enzyme System/genetics , Fibroblasts/cytology , Fibroblasts/drug effects , Humans , Lung/cytology , Microsomes, Liver/metabolism
19.
J Equine Vet Sci ; 134: 105011, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38281609

ABSTRACT

Horses can contribute to the maintenance of grassland. To determine the potential contribution of grassland to horse nutrition, we investigated the seasonal variation of herbage on offer and its nutritional quality in an inventory on six practical horse farms in Central Germany during 2019. On all horse-grazed pastures compressed sward height (CSH) was measured monthly and converted into aboveground herbage (AGH) to allocated short and tall grass sward areas (area-specific) via calibration cuts. In addition, four focus pastures were selected for monthly obtained area-specific herbage quality samples. The farm-specific management was monitored using questionnaires and grazing diaries to determine underlying factors influencing herbage biomass and quality. The proportion of short grass sward areas increased during the grazing season (p=0.0010), which was related to high stocking intensity in terms of livestock unit grazing days (LUGD, p <.0001). On most farms, LUGD were constant throughout the growing season and not adjusted to changing grass growth. Herbage crude protein (CP, p=0.0038), metabolizable energy (ME, p <.0001) concentrations and acid detergent fibre in the organic matter (ADF, p <.0001) differed among the grass sward areas. The results suggest that sufficient ME (4.2 ± 0.32 - 8.4 ± 0.15 MJ ME kg-1 DM) for maintenance and pre-caecal digestible CP (pcdCP) (37.0 ± 3.86 - 77.4 ± 4.44 g kg-1 DM) could be provided during the grazing season. The study highlights the need to incentivise grassland management for herbage provision among horse owners to exploit the potential of grassland during the grazing season.


Subject(s)
Animal Feed , Grassland , Horses , Animals , Farms , Animal Feed/analysis , Poaceae , Seasons
20.
Cytogenet Genome Res ; 139(2): 80-7, 2013.
Article in English | MEDLINE | ID: mdl-23182917

ABSTRACT

The Affymetrix cytogenetic 2.7M whole-genome microarray (Cyto2.7M) detects genomic aberrations. The Cyto2.7M array has increased coverage in regions with cancer-related genes, ~4-fold reduced processing time, and 5-fold reduced input requirements (100 ng) compared to the commonly used Affymetrix SNP6.0 genome-wide microarray (SNP6.0). We set out to compare the performance of these microarrays on cancer samples containing complex genomic changes. We analyzed genomic DNA from 8 lymphoma samples and 1 blood sample using both SNP6.0 and Cyto2.7M microarrays. We compared the arrays with respect to 4 parameters, including detection of copy number variations (CNV), CNV boundaries, the actual copy number (CN) assigned to the aberrations, and loss of heterozygosity. The CN state of selected regions was validated by quantitative PCR. Very high consistency between arrays on all parameters tested was observed, hence only 30 of 224 aberrations disagreed on the CN state, corresponding to a total of ~12 Mb or 0.06% of the analyzed base pairs. Thus, the SNP6.0 and Cyto2.7M arrays are equally well suited to detect genomic aberrations in complex samples such as cancer samples. With reduced processing time and lower input requirements, the Cyto2.7M array enables genomic analysis of samples where only limited DNA is available.


Subject(s)
Cytogenetic Analysis/methods , Genome, Human/genetics , Neoplasms/genetics , Oligonucleotide Array Sequence Analysis/methods , Polymorphism, Single Nucleotide , Chromosome Aberrations , DNA Copy Number Variations , DNA, Neoplasm/genetics , Humans , Loss of Heterozygosity , Polymerase Chain Reaction/methods , Reproducibility of Results
SELECTION OF CITATIONS
SEARCH DETAIL