Biological variations of ADAMTS13 and von Willebrand factor in human adults     

Meltem Kilercik  Abdurrahman Coskun  Mustafa Serteser  Deniz Inan  Ibrahim Unsal 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2014,24(1):138-145

Background:

The ultra-large von Willebrand factor (vWF) multimers are very active and must be degraded by ADAMTS13 for optimal activity. A severe functional deficiency of ADAMTS13 has been associated with thrombotic thrombocytopenic purpura. The correct interpretation of patient vWF and ADAMTS13 plasma levels requires an understanding of the biological variation associated with these analytes. In the present paper, we aimed to determine the biological variation of ADAMTS13 and vWF in human adults.

Materials and methods:

Blood samples were collected weekly from 19 healthy subjects for 5 consecutive weeks. vWF activity and antigenicity were determined using aggregometric and immunoturbidimetric methods. ADAMTS13 antigenicity and activity were determined by ELISA.

Results:

The within-subject biological variations for vWF activity and antigenicity were 8.06% and 14.37%, respectively, while the between-subject biological variations were 18.5% and 22.59%, respectively. The index of individuality for vWF activity was 0.44, while vWF antigenicity was 0.64. Similarly, ADAMTS13 activity and antigenicity within-subject biological variations were 12.73% and 9.75%, respectively, while between-subject biological variations were 9.63% and 6.28%, respectively. The ADAMTS13 indexes of individuality were 1.32 and 1.55, respectively.

Conclusion:

We report high biological variation and individuality in vWF antigenicity and activity levels. However, ADAMTS13 antigenicity and activity displayed high biological variation, but low individuality. Thus, population-based reference intervals may be useful for monitoring ADAMTS13 antigenicity and activity, but not for vWF, which displays high individuality. These findings should be considered when determining the reference interval and other clinical variables associated with ADAMTS13 and vWF levels.  相似文献   

70-year old female patient with mismatch between hematocrit and hemoglobin values: the effects of cold agglutinin on complete blood count     

?erif Ercan  Mustafa ?al??kan  Erhan Koptur 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2014,24(3):391-395

Introduction:

There are a number of pre-analytical and analytical factors, which cause false results in the complete blood count. The present case identifies cold agglutinins as the cause for the mismatch between hematocrit and hemoglobin values.

Materials and methods:

70-year old female patient had a history of cerebrovascular diseases and rheumatoid arthritis. During routine laboratory examination, the patient had normal leukocyte and platelet counts; however, the hemoglobin (Hb: 105 g/L) and hematocrit (HCT: 0.214 L/L) results were discordant. Hemolysis, lipemia and cold agglutinin were evaluated as possible reasons for the mismatch between hematocrit and hemoglobin values.

Results:

First blood sample was slightly hemolysed. Redrawn sample without hemolysis or lipemia was analyzed but the mismatch became even more distinct (Hb: 104 g/L and HCT: 0.08 L/L). In this sample, the titration of the cold agglutinin was determined and found to be positive at 1:64 dilution ratios. After an incubation of the sample at 37°C for 2 hours, reversibility of agglutination was observed.

Conclusion:

We conclude that cold agglutinins may interfere with the analysis of erythrocyte and erythrocyte-related parameters (HCT, MCV, MCH and MCHC); however, Hb, leukocyte and platelet counts are not affected.  相似文献   

Inducing chemotactic and haptotactic cues in microfluidic devices for three-dimensional in vitro assays     

O. Moreno-Arotzena  G. Mendoza  M. Cóndor  T. Rüberg  J. M. García-Aznar 《Biomicrofluidics》2014,8(6)

Microfluidic devices allow for the production of physiologically relevant cellular microenvironments by including biomimetic hydrogels and generating controlled chemical gradients. During transport, the biomolecules interact in distinct ways with the fibrillar networks: as purely diffusive factors in the soluble fluid or bound to the matrix proteins. These two main mechanisms may regulate distinct cell responses in order to guide their directional migration: caused by the substrate-bound chemoattractant gradient (haptotaxis) or by the gradient established within the soluble fluid (chemotaxis). In this work 3D diffusion experiments, in combination with ELISA assays, are performed using microfluidic platforms in order to quantify the distribution of PDGF-BB and TGF-β₁ across collagen and fibrin gels. Furthermore, to gain a deeper understanding of the fundamental processes, the experiments are reproduced by computer simulations based on a reaction-diffusion transport model. This model yields an accurate prediction of the experimental results, confirming that diffusion and binding phenomena are established within the microdevice.  相似文献   

Unsteady flow phenomena in human undulatory swimming: a numerical approach     

Steffen Pacholak  Stefan Hochstein  Alexander Rudert  Christoph Brücker 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(2):176-194

The undulatory underwater sequence is one of the most important phases in competitive swimming. An understanding of the recurrent vortex dynamics around the human body and their generation could therefore be used to improve swimming techniques. In order to produce a dynamic model, we applied human joint kinematics to three-dimensional (3D) body scans of a female swimmer. The flow around this dynamic model was then calculated using computational fluid dynamics with the aid of moving 3D meshes. Evaluation of the numerical results delivered by the various motion cycles identified characteristic vortex structures for each of the cycles, which exhibited increasing intensity and drag influence. At maximum thrust, drag forces appear to be 12 times higher than those of a passive gliding swimmer. As far as we know, this is the first disclosure of vortex rings merging into vortex tubes in the wake after vortex recapturing. All unsteady structures were visualized using a modified Q-criterion also incorporated into our methods. At the very least, our approach is likely to be suited to further studies examining swimmers engaging in undulatory swimming during training or competition.  相似文献   

Anticipatory postural adjustments during cutting manoeuvres in football and their consequences for knee injury risk     

Guillaume Mornieux  Dominic Gehring  Patrick Fürst  Albert Gollhofer 《Journal of sports sciences》2014,32(13):1255-1262

Abstract

Anticipatory postural adjustments (APAs), i.e. preparatory positioning of the head, the trunk and the foot, are essential to initiate cutting manoeuvres during football games. The aim of the present study was to determine how APA strategies during cutting manoeuvres are influenced by a reduction of the time available to prepare the movement.

Thirteen football players performed different cutting tasks, with directions of cutting either known prior to the task or indicated by a light signal occurring 850, 600 or 500 ms before ground contact.

With less time available to prepare the cutting manoeuvre, the head was less orientated towards the cutting direction (P = 0.033) and the trunk was even more rotated in the opposite direction (P = 0.002), while the foot placement was not significantly influenced. Moreover, the induced higher lateral trunk flexion correlated with the increased knee abduction moment (r = 0.41; P = 0.009).

Increasing lateral trunk flexion is the main strategy used to successfully perform a cutting manoeuvre when less time is available to prepare the movement. However, higher lateral trunk flexion was associated with an increased knee abduction moment and therefore an increased knee injury risk. Reducing lateral trunk flexion during cutting manoeuvres should be part of training programs seeking the optimisation of APAs.  相似文献   

Historiography,Cultures of Remembrance and Tradition in German Sport     

Michael Krüger 《国际体育史杂志》2014,31(12):1425-1443

Erinnerungskultur (culture of remembrance) is a widely discussed notion in German historiography. First, the meaning of Erinnerungskultur, including the specific role of academic historiography of sport, is described and explained with respect to sport and sport historiography. One main objective is to reveal the diversity of cultures of sport history and the specific obligations of academic historiography. Second, the actors of sport memories and/or Traditionspflege (heritage) are characterised, and, third, some controversial and perennial debates that permeate German sports history are explained and interpreted, especially that of Carl Diem, internationally known as ‘Mister Olympics’ of 1936. All in all, the paper provides an overview of the mainstreams, cultures and politics of history in Germany with respect to sport.  相似文献   

Writing learning journals: Instructional support to overcome learning-strategy deficits     

Sandra Hübner  Matthias Nückles  Alexander Renkl 《Learning and Instruction》2010,20(1):18-29

Although writing learning journals is a powerful learning tool, instructional support is needed to overcome deficits in the use of self-regulated learning strategies. In a 2 × 2 experimental design with high-school students (N = 70), we analysed the effects of two modes of instruction (namely, informed prompting and learning-journal example) along with prompts. Informed prompting that provided background information on the prompted strategies enhanced learning in the training and transfer session. A learning-journal example that modelled the application of the strategies primarily fostered the strategy used in the training session and learning in the transfer session. Theoretically, the results provide support for the self-regulation view of writing-to-learn.  相似文献   

Neuere Entwicklungen im Unterricht der lebenden Fremdsprachen 2. Seminar des Europarates in London, 12.–23. März 1962     

Hermann Schütt 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》1962,8(2):246-247

Ohne Zusammenfassung  相似文献   

A New Paradigm for Jewish Education     

Stuart Z. Charmé 《Journal of Jewish Education》2013,79(3):179-181

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Besprechungen     

J. Rühl  R. Albrecht 《Sportwissenschaft》1989,19(3):330-334

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