Biorheology - Volume 23, issue s1

Authors: Stoltz, J.F. | Janot, C. | Saur, F. | Weber, M. | Malher, E. | Duvivier, C.

Article Type: Research Article

Abstract: A new electrophoresis system using Laser Doppler velocimetry has been developed. This technic allows fast measurements (1 minute) over a large number of particles (several thousand or more). Furthermore, the small size of the particles is no longer a limitation of the measurement. These qualities made it possible to study the electrokinetic properties of cells. In this paper the authors present the first application obtained on different types of bacteria (Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Proteus vulgaris) submitted to five antibiotics (gentamycin, minocyclin, cephalotin, spiramycin, sobramycin). After four hours or incubation at 37°C, important decreases of electrophoretic mobility …were observed on bacteria treated with antibiotics to which they were sensitive. On the other hand, no significant modification appeared on bacteria treated with antibiotics to which they were not sensitive. In conclusion, the electrophoretic mobility test seems to be useful to study the response of bacteria to antibiotics and perhaps could be used to set antibiograms. Show more

Keywords: Laser-Doppler electrophoresis, surface charge, bacteria, antibiotics

DOI: 10.3233/BIR-1984-23S154

Citation: Biorheology, vol. 23, no. s1, pp. 303-307, 1984

Authors: Leterrier, François | Berleur, François | Viret, Jacques | Daveloose, Denis

Article Type: Research Article

Abstract: One of the most powerful tools for the study of the molecular dynamics and molecular organization of biological membranes is the spin label method which uses stable free radicals (nitroxides) studied by electron spin resonance spectroscopy. The spectra are very dependent on the mobility and orientation of these probes in a magnetic field. They give information on the tumbling rate of molecules in liquids, the membrane microviscosity, the order parameter of the phospholipid fatty acid chains, the activation energy of their rotation and their flexibility. The method has interesting applications in the rheological domain; for example it enables measurement of …the internal viscosity of erythrocytes and red blood cell orientation in a Poiseulle flow. Show more

Keywords: Spin labelling, RBC internal viscosity, RBC orientation

DOI: 10.3233/BIR-1984-23S155

Citation: Biorheology, vol. 23, no. s1, pp. 309-314, 1984

Authors: Andre, J.C. | Donner, M. | Bouchy, M. | Viriot, M.L. | Jezequel, J.Y. | Stoltz, J.F.

Article Type: Research Article

Abstract: It is possible to characterize the cohesion of the lipidic zones in cells or in membranes by using molecular emission spectroscopy techniques such as: fluorescence polarization, quenching reactions, intramolecular reactions. However, applying these techniques in biology can be improved by the use of pulsed excitations leading to the time-resolved evolutions of some properties of the probe, which can themselves be a function of their environment. The first and the last techniques, based on the use of diphenylhexatriene and dipyrenylpyopane respectively are used in practice by steady state excitation. In the case of fluorescence polarization, it can be shown that …the method can be applied, within certain limits, which have to be precised when studying the modifications in the membranes. This is also partly true for methods based on the use of intramolecular reactions. However these continuous excitation techniques usually only lead to a global result which is a function of several spectroscopic parameters and of the “cohesion” of the membrane. Then it can be shown that to go beyond this step of semi-quantitative analysis, it is necessary to use pulsed or modulated excitation methods. Moreover this more sophisticated technical approach implies a new theoretical effort to understand the molecular dynamics of the membranes. Show more

Keywords: cellular rheology, photophysical methods, fluorescence polarization

DOI: 10.3233/BIR-1984-23S156

Citation: Biorheology, vol. 23, no. s1, pp. 315-322, 1984

Authors: Koyama, T. | Araiso, T. | Shindo, Y. | Arai, T.

Article Type: Research Article

Abstract: A nanosecond fluorometer was designed to study the microdynamics of biomembranes. The overall system consists of a nitrogen laser for excitation of fluorophores, optics consisting of polarizers, monochromators, a single photon counting system having a multichannel time to amplitude converter controlled with a microcomputer and a data processing system. The laser pulse for excitation was polarized with a polarizer. Anisotropically polarized DPH fluorescence could be measured with a time resolution smaller than 5 nsec. The parallel decay curve of DPH fluorescence was higher than the perpendicular decay curve in erythrocyte membrane over the whole decay time. No anisotropism was recorded …in a tetrahydrofuran solution. These results suggested that the motion of DPH molecules in erythrocyte membranes was restrained and that the present system provided information on rheological aspects of molecular dynamic structure of biomembranes. Show more

Keywords: nanosecond fluorometer, erythrocyte membrane, anisotropy, microrheology, wobbling motion, fluorophore

DOI: 10.3233/BIR-1984-23S157

Citation: Biorheology, vol. 23, no. s1, pp. 323-329, 1984

Authors: Viriot, M.L. | Collin, T. | Gaillard, S. | Stoltz, J.F. | Andre, J.C.

Article Type: Research Article

Abstract: Intramolecular excimer formation of dipyrenylpropane was investigated in human blood platelets. The ratio of the emission intensities of excimer to monomer (IE /IM ) is sensitive to changes in lipidic membrane structure, induced by external perturbations, such as cholesteryl hemisuccinate introduction and temperature. Lack of reliable “microviscosities” determinations could be due to poor solubility of the probe in aqueous cells suspensions. Results were compared to those obtained with the fluorescence polarization technique.

Keywords: blood platelets, fluorescence spectroscopy

DOI: 10.3233/BIR-1984-23S158

Citation: Biorheology, vol. 23, no. s1, pp. 331-333, 1984

Authors: Steiner, C.A. | Litt, M. | Nossal, R.

Article Type: Research Article

Abstract: Variables which describe the structure and rheological behavior of macromolecules in both dilute solutions and gels may be determined using methods of quasielastic laser light scattering (QELS). Such parameters include diffusion coefficients, molecular size such as hydrodynamic radius, and viscoelastic moduli. If the polymer is polydisperse, the distribution of radii may be estimated. Application of the methods is illustrated with data on the size distribution of a tracheal mucin glycoprotein solution as an example of a polydisperse polymer solution of biorheological interest. A scheme for measuring shear moduli of polymer gels using dynamic laser light scattering is illustrated with data …on reconstituted fibrin clots. Show more

Keywords: Laser light scattering, mucin structure, gel rheology, fibrin gels

DOI: 10.3233/BIR-1984-23S159

Citation: Biorheology, vol. 23, no. s1, pp. 335-344, 1984

Authors: Peslin, R. | Duvivier, C. | Hannhart, B.

Article Type: Research Article

Abstract: A synthetic approach to lung and chest mechanics is to apply pressure variations to the respiratory system over a range of frequencies and to study the amplitude and phase relationships between applied pressure and resulting gas or tissue flow. Such impedance measurements may be performed in different ways, which are not equivalent: the most usual are to measure gas flow at the mouth while pressure is varied either at the same place (input impedance) or around the chest (transfer impedance). Transfer impedance measurements were performed in healthy subjects from 3 to 70 Hz and tentatively interpreted with a model featuring …tissue elasticity, resistance and inertance, gas compressibility, and airway gas resistance and inertance. The pressure-flow ratio was minimum at 5–10 Hz and increased very fast above 50 Hz. The phase angle was nil around 7 Hz, of + 90° at 30–40 Hz and close to 180° at 70 Hz. The validity of the model is supported by the quality of the fit to the data up to 50 Hz, the values of the coefficients and the results of experiments where the subject’s mechanical properties were varied. Show more

DOI: 10.3233/BIR-1984-23S132

Citation: Biorheology, vol. 23, no. s1, pp. S183-S191, 1984

Authors: Teitel, P. | Malotta, H. | Leschke, M. | Schmid-Schönbein, H.

Article Type: Research Article

Abstract: Nuclepore filter membranes currently utilized to assess RBC “deformability” do not meet the strict metrological requirements of a measuring gauge. They present different kinds of inhomogeneities introducing an useless information (a background noise) into measurement results and expressed as poor reproducibility. Variance reduction can only be achieved by eliminating aberrant results from a series of parallel measurements made with different membranes. To this end a procedure is proposed to identify aberrant values by an iterative statistical regression analysis of data from filter calibration and measurements on RBC suspensions and to express results as “reduced” initial flow rates for a standard …filter resistance. Show more

DOI: 10.3233/BIR-1984-23S140

Citation: Biorheology, vol. 23, no. s1, pp. S231-S240, 1984

Authors: Duvivier, C. | Arnould, J.P. | Malher, E. | Fourneau, C. | Stoltz, J.F.

Article Type: Research Article

Abstract: A device for continuously measuring, at constant pressure, the filtration resistance of different liquid suspensions is described. It is made up of two main parts: flowmeter system and electronic circuit. The flowmeter consists of a capillary tube and a sensitive pressure transducer, and has a time response of 100 ms and a linearity of ± 1 % from 1 μ ls−1 to 200 μ ls−1 . The electronic part allows the calculation and recording of flow versus time and filtration resistance versus the volume which passes through the filter. Principle, technical characteristics of the system and examples of recording …with several Red Blood Cell populations are reported. Show more

Keywords: filterability, erythrocytes, constant pressure

DOI: 10.3233/BIR-1984-23S147

Citation: Biorheology, vol. 23, no. s1, pp. S271-S274, 1984

Authors: Plouvier, S.R. | Huong, Pham V.

Article Type: Research Article

Abstract: The microscopic observation of blood under various pathological circumstances (infectious diseases, cancer, leukemia) shows the presence of blue particles of micrometer size. Microbial cultivation of such blood samples allows the isolation of bacteria able to produce such chromophore particles in vitro, when cultivated on medium containing prewarmed blood (Chocolate Blood Medium) and to provoke the appearance of that material in normal blood, initially free from it. The vibrational spectra of these micrometer size coloured particles have been recorded by a micro-Raman Spectrometer and the identical nature of the blue particles from the two different sources has been well established. These …findings suggest that the blue particles in pathological blood are originated by bacteria. The circumstances of the discovery of the microbial chromophore materials in blood, particularly but non exclusively in cases of cancer or leukemia can be discussed in comparison with the other pathogenic mechanisms. Show more

DOI: 10.3233/BIR-1984-23S160

Citation: Biorheology, vol. 23, no. s1, pp. S345-S347, 1984

Authors: Chien, Shu

Article Type: Other

Keywords: Blood, Cell deformability, Membranes, Methodology, Viscometer

DOI: 10.3233/BIR-1984-23S161

Citation: Biorheology, vol. 23, no. s1, pp. S349-S354, 1984