http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Improved assessment of frozen/thawed mouse spermatozoa using fluorescence microscopy
Ann-Kathrin Diercks,Heinrich F. Bürgers,Anna Schwab,Johannes Schenkel 대한수의학회 2012 Journal of Veterinary Science Vol.13 No.3
Genetically modified (GM) animals are unique mutants with an enormous scientific potential. Cryopreservation of pre-implantation embryos or spermatozoa is a common approach for protecting these lines from being lost or to store them in a repository. A mutant line can be taken out of a breeding nucleus only if sufficient numbers of samples with an appropriate level of quality are cryopreserved. The quality of different donors within the same mouse line might be heterogeneous and the cryopreservation procedure might also be error-prone. However, only limited amounts of material are available for analysis. To improve the monitoring of frozen/thawed spermatozoa, commonly used in vitro fertilization (IVF) followed by embryo transfer were replaced with animal-free techniques. Major factors for assessing spermatozoa quality (i.e., density, viability, motility, and morphology) were evaluated by fluorescence microscopy. For this, a live/dead cell staining protocol requiring only small amounts of material was created. Membrane integrity was then examined as major parameter closely correlated with successful IVF. These complex analyses allow us to monitor frozen/thawed spermatozoa from GM mice using a relatively simple staining procedure. This approach leads to a reduction of animal experiments and contributes to the 3R principles (replacement, reduction and refinement of animal experiments).
Deborah B. Diercks,Kelly P. Owen,Jeffrey A. Kline,Mark E. Sutter 대한응급의학회 2016 Clinical and Experimental Emergency Medicine Vol.3 No.4
Objective Contrast induced nephropathy (CIN) is a result of injury to the proximal tubules. The incidence of CIN is around 11% for imaging done in the acute care setting. We aim to analyze the metabolic patterns in the urine, before and after dosing with intravenous contrast for computed tomography (CT) imaging of the chest, to determine if metabolomic changes exist in patients who develop CIN. Methods A convenience sample of high risk patients undergoing a chest CT with intravenous contrast were eligible for enrollment. Urine samples were collected prior to imaging and 4 to 6 hours post imaging. Samples underwent gas chromatography/mass spectrometry profiling. Peak metabolite values were measured and data was log transformed. Significance analysis of microarrays and partial least squares was used to determine the most significant metabolites prior to CT imaging and within subject. Analysis of variance was used to rank metabolites associated with temporal change and CIN. CIN was defined as an increase in serum creatinine level of ≥ 0.5 mg/dL or ≥ 25% above baseline within 48 hours after contrast administration. Results We sampled paired urine samples from 63 subjects. The incidence of CIN was 6/63 (9.5%). Patients without CIN had elevated urinary citric acid and taurine concentrations in the pre-CT urine. Xylulose increased in the post CT sample in patients who developed CIN. Conclusion Differences in metabolomics patterns in patients who do and do not develop CIN exist. Metabolites may be potential early identifiers of CIN and identify patients at high-risk for developing this condition prior to imaging.
Can a Point-of-Care Troponin I Assay be as Good as a Central Laboratory Assay? A MIDAS Investigation
W. Frank Peacock,Deborah Diercks,Robert Birkhahn,Adam J. Singer,Judd E. Hollander,Richard Nowak,Basmah Safdar,Chadwick D. Miller,Mary Peberdy,Francis Counselman,Abhinav Chandra,Joshua Kosowsky,James N 대한진단검사의학회 2016 Annals of Laboratory Medicine Vol.36 No.5
Background: We aimed to compare the diagnostic accuracy of the Alere Triage Cardio3 Tropinin I (TnI) assay (Alere, Inc., USA) and the PathFast cTnI-II (Mitsubishi Chemical Medience Corporation, Japan) against the central laboratory assay Singulex Erenna TnI assay (Singulex, USA). Methods: Using the Markers in the Diagnosis of Acute Coronary Syndromes (MIDAS) study population, we evaluated the ability of three different assays to identify patients with acute myocardial infarction (AMI). The MIDAS dataset, described elsewhere, is a prospective multicenter dataset of emergency department (ED) patients with suspected acute coronary syndrome (ACS) and a planned objective myocardial perfusion evaluation. Myocardial infarction (MI) was diagnosed by central adjudication. Results: The C-statistic with 95% confidence intervals (CI) for diagnosing MI by using a common population (n=241) was 0.95 (0.91-0.99), 0.95 (0.91-0.99), and 0.93 (0.89-0.97) for the Triage, Singulex, and PathFast assays, respectively. Of samples with detectable troponin, the absolute values had high Pearson (RP) and Spearman (RS) correlations and were RP =0.94 and RS=0.94 for Triage vs Singulex, RP =0.93 and RS=0.85 for Triage vs PathFast, and RP =0.89 and RS=0.73 for PathFast vs Singulex. Conclusions: In a single comparative population of ED patients with suspected ACS, the Triage Cardio3 TnI, PathFast, and Singulex TnI assays provided similar diagnostic performance for MI.
William R. Fox,Deborah B. Diercks 대한응급의학회 2016 Clinical and Experimental Emergency Medicine Vol.3 No.1
Troponins are proteins commonly found in cardiac tissue that are released during myocardial ischemia or necrosis. These troponins can be detected by assays that can then be used to guide clinical decision-making and disposition, especially if the suspected insult is related to acute coronary syndrome. Timing of troponin measurement can be important as elevations may not be detectible immediately after an insult. New assays have been designed to detect troponin concentrations previously too low to be detected by conventional assays. These tests are known as high-sensitivity cardiac troponin assays. Current research is aimed at evaluating the clinical significance of troponin elevations detected by these new assays especially in management of patients with suspected acute coronary syndrome. A number of risk-stratification scores exist to assist physicians with evaluating chest pain in the emergency department in the context of detection (or absence) of troponins in systemic circulation. Additionally, investigators are working to integrate data generated by hs-cTn measurements into existing and new risk-stratification scores.
Hwang, Jun Yeon,Banerjee, Rajarshi,Diercks, David R.,Kaufman, Michael J. Korean Society of Microscopy 2013 Applied microscopy Vol.43 No.3
The heterogeneous nucleation of the ${\Theta}^{\prime}$ phase on nanoscale precipitates has been investigated using a combination of three-dimensional atom probe tomography and high-resolution transmission electron microscopy. Two types of ${\Theta}^{\prime}$ phases were observed, namely small (~2 nm thick) cylindrical precipitates and larger (~100 nm) globular precipitates and both appear to be heterogeneously nucleated on the nanoscale precipitates. The composition and crystal structure of precipitates were directly analyzed by combination of two advanced characterization techniques.
A Trap Motion in Validating Muscle Activity Prediction from Musculoskeletal Model using EMG
Wibawa, A. D,Verdonschot, N,Halbertsma, J. P. K,Burgerhof, J. G. M,Diercks, R. L,Verkerke, G. J 보안공학연구지원센터 2016 International Journal of Bio-Science and Bio-Techn Vol.8 No.6
Musculoskeletal modeling nowadays is becoming the most common tool for studying and analyzing human motion. Besides its potential in predicting muscle activity and muscle force during active motion, musculoskeletal modeling can also calculate many important kinetic data that are difficult to measure in vivo, such as joint force or ligament force. This paper will validate muscle activity predicted by the model during a static motion like knee flexion motion (squat motion). In this experiment, knee flexion motion was performed by 5 healthy subjects and modeled by using Gait Lower Extremity model from AnyBody Modeling System (AMS). Eight lower limb muscle activity prediction from the model will be validated by 8 EMG electrodes that measured the same muscles during squat motion. Muscle activity pattern and the position of onset would be used as a key factor in this validation study. Pearson correlation coefficient will be used to compare the pattern of both graphs. Knee joint force prediction from the model will also be compared with the literature studies. The result showed that 3 muscles showed high correlation coefficient, while the other 4 muscles showed slightly medium and one showed low correlation. Time delay of muscle activation between the model and EMG was recorded from Vastus Medialis muscle (18.38 ms) and Vastus Lateralis (22.8 ms), with muscle activation from the model was late compared to EMG. In conclusion, this statistical study has shown some detail differences between EMG and muscle activity prediction from the model. Knee flexion motion can be used as a trap motion when validating muscle activity of a musculoskeletal model, because the model will activate muscle activity based on motion data of markers, while in knee-flexed position, there was no marker’s movement, but the EMG was highly active due to the posture of the subjects in maintaining the knee-flexed position. However, the knee compressive force prediction from the model has showed positive confirmation from the literatures.
Peacock W. Frank,Maisel Alan S.,Mueller Christian,Anker Stefan D.,Apple Fred S.,Christenson Robert H.,Collinson Paul,Daniels Lori B.,Diercks Deborah B.,Somma Salvatore Di,Filippatos Gerasimos,Headden 대한응급의학회 2022 Clinical and Experimental Emergency Medicine Vol.9 No.2
Objective To determine the utility of a highly sensitive troponin assay when utilized in the emergency department.Methods The FAST-TRAC study prospectively enrolled >1,500 emergency department patients with suspected acute coronary syndrome within 6 hours of symptom onset and 2 hours of emergency department presentation. It has several unique features that are not found in the majority of studies evaluating troponin. These include a very early presenting population in whom prospective data collection of risk score parameters and the physician’s clinical impression of the probability of acute coronary syndrome before any troponin data were available. Furthermore, two gold standard diagnostic definitions were determined by a pair of cardiologists reviewing two separate data sets; one that included all local troponin testing results and a second that excluded troponin testing so that diagnosis was based solely on clinical grounds. By this method, a statistically valid head-to-head comparison of contemporary and high sensitivity troponin testing is obtainable. Finally, because of a significant delay in sample processing, a unique ability to define the molecular stability of various troponin assays is possible.Trial registration ClinicalTrials.gov Identifier NCT00880802