Off-patient assessment of pre-cordial impact mechanics among medical professionals in North-East Italy involved in emergency cardiac resuscitation.
Pellis, T., Pausler, D., Gaiarin, M., Franceschino, E., Epstein, A., Boulin, C. & Kohl, P.
Prog Biophys Mol Biol. 2012 Oct;110(2-3):390-6. doi:10.1016/j.pbiomolbio.2012.08.002. Epub 2012 Aug 11.
Pre-cordial thump (PT) relies on cardiac mechano-electric transduction to transform mechanically-delivered energy into an electrophysiologically relevant stimulus. Its use for emergency resuscitation has declined recent years, amidst concerns about effectiveness and side-effects. In addition, there is insufficient knowledge about bio-mechanical properties and mechanisms of PT. Using a PT-mechanics recorder, we measured PT off-patient among healthcare professionals (n = 58) in North-East Italy, and related this to retrospective information on self-reported PT outcomes. Impact-speed and peak-force were 4.7 +/- 1.3 m s(-1) (2.2-7.8 m s(-1)) and 394 +/- 110 N (202-648 N), respectively. Average self-reported cardioversion rate by PT was 35%. No adverse events were stated. All but 3 of PT providers with self-reported cardioversion rates >/=50% had pre-impact fist-speeds of >/=3.7 m s(-1). In comparison with previously-reported data from UK and US (n = 22 each), self-reported success-rates and pre-impact fist-speeds were more similar to US (PT-induced cardioversion rate 27.7%; fist-speed 4.17 +/- 1.68 m s(-1)) than to UK participants (PT-induced cardioversion rate 13.3%; fist-speed 1.55 +/- 0.68 m s(-1)). Small cohort-size, retrospective nature of data-gathering, and 'self-selection bias' (participants who have used PT on patients) limits the extent to which firm conclusions can be drawn. Observations are compatible, though, with the possibility that pre-impact fist-speed may affect success-rate of PT. Thus, where PT is used for acute resuscitation, it is delivered because it is immediately 'at hand'. Negative side effects are rare or absent in witnessed cardiac arrest cases. Pre-impact fist-speed may be a determinant of outcome, and this could be trained using devices suitable for self-assessment.
In migrating cells, the Golgi complex and the position of the centrosome depend on geometrical constraints of the substratum.
Pouthas, F., Girard, P., Lecaudey, V., Ly, T.B., Gilmour, D., Boulin, C., Pepperkok, R. & Reynaud, E.G.
J Cell Sci. 2008 Jul 15;121(Pt 14):2406-14. Epub 2008 Jun 24.
Although cells migrate in a constrained 3D environment in vivo, in-vitro studies have mainly focused on the analysis of cells moving on 2D substrates. Under such conditions, the Golgi complex is always located towards the leading edge of the cell, suggesting that it is involved in the directional movement. However, several lines of evidence indicate that this location can vary depending on the cell type, the environment or the developmental processes. We have used micro contact printing (microCP) to study the migration of cells that have a geometrically constrained shape within a polarized phenotype. Cells migrating on micropatterned lines of fibronectin are polarized and migrate in the same direction. Under such conditions, the Golgi complex and the centrosome are located behind the nucleus. In addition, the Golgi complex is often displaced several micrometres away from the nucleus. Finally, we used the zebrafish lateral line primordium as an in-vivo model of cells migrating in a constrained environment and observe a similar localization of both the Golgi and the centrosome in the leading cells. We propose that the positioning of the Golgi complex and the centrosome depends on the geometrical constraints applied to the cell rather than on a precise migratory function in the leading region.
Soft tissue impact characterisation kit (STICK) for ex situ investigation of heart rhythm responses to acute mechanical stimulation.
Cooper, P.J., Epstein, A., Macleod, I.A., Schaaf, S.T., Sheldon, J., Boulin, C. & Kohl, P.
Prog Biophys Mol Biol. 2006 Jan-Apr;90(1-3):444-68. Epub 2005 Aug 9.
Both mechanical induction and mechanical termination of arrhythmias have been reported in man. Examples include pre-cordial impacts by sports implements (baseballs, pucks) that can trigger arrhythmias, including ventricular fibrillation, or via the so-called pre-cordial thump, used as an emergency resuscitation measure to convert arrhythmias to normal sinus node rhythm. These interventions have been partially reproduced in experimental studies on whole animals. Relating observations at the system's level to underlying mechanisms has been difficult, however, largely because of: (i) a deficit in efficient and affordable pharmacological agents to selectively target (sub-)cellular responses in whole animal studies, and (ii) the lack of suitable experimental models to study the above responses at intermediate levels of functional and structural integration, such as the isolated heart or cardiac tissue. This paper presents a soft tissue impact characterisation kit (STICK), suitable for quantitative investigations into the effects of acute mechanical stimulation on cardiac electro-mechanical function in rodent isolated heart or tissue preparations. The STICK offers independent control over a range of relevant biophysical parameters, such as impact location and energy, pre-impact projectile speed and contact area, as well as over the timing of a mechanical stimulus relative to the cardiac cycle (monitored via electrocardiogram, ECG, here recorded directly from the cardiac surface). Projectile deceleration upon interaction with the tissue is monitored, contact-free, with a resolution of 175 microm, providing information on tissue deformation dynamics, force, pressure and work of the mechanical intervention. In order to study functional effects of cardiac mechanical stimulation in the absence of tissue damage, impacts must be limited (for juvenile Guinea pig heart) to 2-2.5 mJ in the slack left ventricle (diastolic impact) and 5-10 mJ in contracture (systolic impact), as confirmed by enzyme assay and histological investigation. Impacts, timed to coincide with the early T-wave of the ECG, are capable of triggering short runs of ventricular fibrillation. Thus, the STICK is a suitable tool for the study of acute cardiac mechano-electric feedback effects, caused by short impulse-like mechanical stimulation, at the level of the isolated organ or tissue.
Automatisierte DNA-Extraktion durch Kombination von Liquid Handling und Zentrifugation.
Zimmermann, J., Zinn, T., Benes, V., Ibberson, D., Boulin, C., Griebel, R., Lomax, P., Mausel, M., Schubell, U. & Gunther-Eberle, K.
Laborwelt 2003 4(5) 41-42
A parallel systolic array ASIC for real-time execution of the Hough transform.
Epstein, A., Paul, G.U., Vettermann, B., Boulin, C. & Klefenz, F.
IEEE Trans. on Nuclear Science 2002 49(2) 339-346
Many pattern recognition problems can be solved by mapping the input data into an n-dimensional feature space in which a vector indicates a set of attributes. One powerful pattern recognition method is the Hough transform. In reducing the n-dimensional feature space to two dimensions, the coordinate transform can be executed by a systolic array consisting of time-delay processing elements and adders. The application-specific integrated circuit (ASIC) implementation of the Hough transform as a systolic array for real-time recognition of curved tracks in multiwire drift chambers is presented. The array can handle 32 parallel input data streams. It mainly consists of 512 identical programmable processing elements. Sixteen histogram pixels in the feature space are produced in parallel per clock cycle. The ASIC is implemented in 0.6 mum CMOS, two-metal layer technology (CUB) from Austria Micro Systems (AMS) and operates with a clock frequency of 100 MHz. The interconnectivity pattern of the processing elements required to initialize the chip according to the pattern recognition task is computed on the host computer using the Hough-transform equations. This pattern is then downloaded to the chip via the data input lines. The Hough-transform ASIC is suitable for a wide range of pattern recognition applications. The integrated circuit is a powerful building block for systems requiring real-time execution of the Hough transform.
The PASERO Project: Parallel and Serial Readout systems for gas proportional synchrotron radiation X-ray detectors.
Koch, M.H.J., Boulin, C., Briquet-Laugier, B., Epstein A., Sheldon, S., Beloeuvre, E., Gabriel, A., Herve, C., Kocsis, M., Koschuch, A., Laggner, P., Leingartner, W., de Raad Iseli, C., Reimann, T., Golding, F. & Torki, K.
Nuclear Instrum. and Methods 2001 (A467-468) 1156-1159
A data acquisition system for gas proportional detectors with delay line readout based on space-time-space conversion.
de Raad Iseli, C., Reimann, T., Golding, G., Boulin, C., Epstein, A., Beloeuvre, E., Gabriel, A. and Koch & M.H.J.
Nuclear Instrum. Methods 2001 (A467-468) 1152-1155
A NIM module for delay line readout of linear gas proportional X-ray or neutron detectors based on time to space conversion is presented. Each of the 16 ASICs in the module contains a delay line with 64 elements each connected to a 24 bit-counter. Readout of the coincidence of signals travelling in opposite directions on the delay line and incrementation of the counters is triggered by the prompt anode signal so that simultaneous events are correctly processed. Transfer of the contents of the 1024 individual counters to a histogramming device at the end of a time frame can be as short as 60 mus. With continuous delay lines the total conversion time equals the transit time of the delay line in the detector, whereas with segmented delay lines the total conversion time is around 20 ns.
Fast wire per wire X-ray data acquisition system for time resolved small angle scattering experiments
Epstein, A., Briquet-Laugier, F., Sheldon, S. & Boulin, C.
Proc. XIth IEEE Real Time Conference 1999 316-321
General purpose RISC based unit: a building block for fast data acquisition systems.
Epstein, A. & Boulin, C.
Proc. XIth IEEE Real Time Conference 1999 313-315
Real-time software for a wire per wire parallel readout X-ray data acquisition system.
Briquet-Laugier, F., Baumlin, P., Boulin, C., Golding, F., Koch, M.H.J & Epstein, A.
Proc. XIth IEEE Real Time Conference 1999 129-133
A role for microtubule dynamics in phagosome movement.
Blocker, A., Griffiths, G., Olivo, J.C., Hyman, A.A. & Severin, F.F.
J Cell Sci 1998 Feb 111 ( Pt 3) 303-312
We have shown previously that intracellular phagosome movement requires microtubules. Here we provide evidence that within cells phagosomes display two different kinds of microtubule-based movements in approximately equal proportions. The first type occurs predominantly in the cell periphery, often shortly after the phagosome is formed, and at speeds below 0.1 microm/second. The second is faster (0.2-1.5 micron/second) and occurs mainly after phagosomes have reached the cell interior. Treating cells with nanomolar concentrations of taxol or nocodazole alters microtubule dynamics without affecting either total polymer mass or microtubule organisation. Such treatments slow the accumulation of phagosomes in the perinuclear region and reduce the number of slow movements by up to 50% without affecting the frequency of fast movements. This suggests that a proportion of slow movements are mediated by microtubule dynamics while fast movements are powered by microtubule motors. In macrophages, interphase microtubules radiate from the microtubule organising centre with their plus-end towards the cell periphery. To understand the behaviour of 'early' phagosomes at the cell periphery we investigated their ability to bind microtubule plus-ends in vitro. We show that early phagosomes have a strong preference for microtubule plus-ends, whereas 'late' phagosomes do not, and that plus-end affinity requires the presence of microtubule- associated proteins within cytosol. We suggest that phagosomes can bind to the plus-ends of dynamic microtubules and move by following their shrinkage or growth.
A RISC based SCSI interface for a protein crystallography detector.
Epstein, A., Baumlin, P. & Boulin, C.
IEEE Trans. on Nuclear Science 1998 45(4) 1934-1936
A fast position encoding system for delay line based gas filled area detector.
Epstein, A. & Boulin, C.
IEEE Trans. on Nucl. Science 1998 45 1931-1933
A fully automated image acquisition and analysis system for low light level fluorescence microscopy.
Herr, S., Bastian, T., Pepperkok, R., Boulin, C. & Ansorge, W.
Meth Mol Cell Biol 1993 40 164-170