Purchase individual online access for 1 year to this journal.
Price: EUR 90.00
Impact Factor 2020: 0.889
Biorheology is an international interdisciplinary journal that publishes research on the deformation and flow properties of biological systems or materials. It is the aim of the editors and publishers of
Biorheology to bring together contributions from those working in various fields of biorheological research from all over the world. A diverse editorial board with broad international representation provides guidance and expertise in wide-ranging applications of rheological methods to biological systems and materials.
The aim of biorheological research is to determine and characterize the dynamics of physiological processes at all levels of organization. Manuscripts should report original theoretical and/or experimental research promoting the scientific and technological advances in a broad field that ranges from the rheology of macromolecules and macromolecular arrays to cell, tissue and organ rheology. In all these areas, the interrelationships of rheological properties of the systems or materials investigated and their structural and functional aspects are stressed.
The scope of papers solicited by
Biorheology extends to systems at different levels of organization that have never been studied before, or, if studied previously, have either never been analyzed in terms of their rheological properties or have not been studied from the point of view of the rheological matching between their structural and functional properties. This biorheological approach applies in particular to molecular studies where changes of physical properties and conformation are investigated without reference to how the process actually takes place, how the forces generated are matched to the properties of the structures and environment concerned, proper time scales, or what structures or strength of structures are required.
Biorheology invites papers in which such 'molecular biorheological' aspects, whether in animal or plant systems, are examined and discussed. While we emphasize the biorheology of physiological function in organs and systems, the biorheology of disease is of equal interest. Biorheological analyses of pathological processes and their clinical implications are encouraged, including basic clinical research on hemodynamics and hemorheology.
In keeping with the rapidly developing fields of mechanobiology and regenerative medicine,
Biorheology aims to include studies of the rheological aspects of these fields by focusing on the dynamics of mechanical stress formation and the response of biological materials at the molecular and cellular level resulting from fluid-solid interactions. With increasing focus on new applications of nanotechnology to biological systems, rheological studies of the behavior of biological materials in therapeutic or diagnostic medical devices operating at the micro and nano scales are most welcome.
Abstract: The transepithelial potential difference (PD) value represents an integral of ion fluxes across the epithelium, and relates to the regulation of airway fluid. We studied six healthy two day old husky puppies for their tracheal mucus rheology and bioelectric properties, since this data in newborns are still unknown. PD (-mV, epithelium vs. subcutaneous space) was measured using the agar bridge technique in two locations - lower trachea and subglottic region. For the rheological analysis, the magnetic microrheometer was employed; data are presented as mechanical impedance log G* and loss tangent tan δ (1 rad/s). The mucus collection rate (mg/min)…and the solid content (%) were determined by gravimetry. Mucociliary clearability, normalized to frog mucus, (MCFP) was determined directly by the frog palate method; a cough clearability index (CCI) was computed from simulated cough machine data obtained with mucus-like gels. The mucus collection rates and PD values were considerably lower than those observed in adult dogs; the mechanical impedance values were also reduced in comparison with adult data. The PD profile (-13.9 ± 1.2 mV lower trachea vs. -18.4 ± 1.4 mV subglottical, i.e. more negative subglottically), however, is similar to that observed in adult dogs. Intratracheal profiles in mucus collection rate and mucus rheology were also comparable between puppies and adult dogs. The low collection rates in puppies, particularly in lower trachea, could indicate either reduced mucus volume or slower clearance. PD and collection rate correlated very strongly (r = 0.82, p = 0.0003). PD also correlated negatively with log G* (r = 0.73, p = 0.003) and positively with tan δ (r = 0.58, p = 0.03). MCFP and % solids correlated positively (r = 0.84, p = 0.0012), in contradistinction to the usual relationship, perhaps due to the presence of non-glycoprotein components that do not contribute to crosslink formation. The apparent maturation of airway bioelectric properties, mucus collection rate and mucus viscoelasticity are all consistent with the maturation of mucociliary clearance, which has previously been reported.
Abstract: The cilia that propel mucus are specialised for the function in their arrangement length, some details of structure, beat pattern, beat cycle characteristics, metachronal coordination, local control of beat rate by response to mechanical stimulation and generalised control of beat rate by neurohormones. These features are matched to the properties of the visco-elastic mucus gel that is propelled at the ciliary tips above a low-viscosity periciliary layer whose depth must be regulated within defined limits.
Abstract: A computer-assisted transillumination, photoelectronic technique has been used to measure the beat frequency of cilia of rabbit tracheal cells grown in culture. When ciliated cells arc mechanically stimulated with a microprobe the cells respond rapidly by increasing the beat frequency of their cilia. This mechanosensitive response is not limited to the stimulated cell, but is communicated in all directions to neighboring cells. To characterize the progression of this communicated response we used an automated computer-assisted imaging system to examine high-speed films of responding cells. The time it takes for the response to be transmitted between cells is slow (1-3 sec)…with each cell responding after a lag-time that is proportional to the distance of the cell from the stimulated cell. We have confirmed that gap junctions are present between cells and that adjacent or non-adjacent ciliated, as well as non-ciliated, cells are electrically coupled. To correlate the mechanosensitive response with intracellular calcium fluxes we have used fura-2, a calcium-specific fluorescent dye, and digital video microscopy. Mechanical stimulation of the cultured ciliated cells, in the presence of extracellular calcium, resulted in an initial increase in intracellular calcium, which was communicated to neighboring cells. Without extracellular calcium, mechanosensitivity of cultured cells was lost and a small decrease in intracellular calcium was observed in the stimulated cell. However, neighboring cells still displayed an increase in intracellular calcium. The time course and general pattern of calcium increase in adjacent cells was similar to the responses in ciliary activity produced by mechanical stimulation. Ciliary beat frequency is also elevated by f3-adrenergic drugs independently of mechanosensitivity. These responses are important because they could provide a dual regulatory mechanism for the control of mucus transport. Adrenergic agonists could provide non-specific control by increasing ciliary activity throughout the airways while mechanosensitivity could provide local control by increasing activity in those regions of heavy mucus load.
Keywords: Cilia, Mechanosensitivity, Intracellular calcium, Intercellular communication
vol. 27, no. 3-4, pp. 533-545, 1990
Abstract: Ciliary metachronism and motility were examined optically in muco-ciliary tissue cultures from three different systems: a) frog’s palate epithelium, b) frog’s oesophagus, and c) human nasal polyps. In addition, lateral cilia of Mytilus edulis (water transporting cilia) were examined. It was revealed that the degree of synchronization between muco-ciliary systems is lower than that of water transporting cilia. There are no significant differences between different muco-ciliary systems, within the accuracy of of measurement although relatively large statistical ensembles were used. In addition the wavelength and wave direction of the metachronal wave was examined. All four systems exhibit similar wavelength. The…metachronal parameters of muco-ciliary systems exhibit fluctuations (as was demonstrated by the degree of synchronization), however, the magnitude and repetitivity of these fluctuations, is dependent on the loading of the ciliary system. We have loaded the system by increasing the viscosity of the medium. Under viscous load the frequency of the beating decreased. The metachronal wavelength became longer and the metachronal coordination type more orthoplectic.
Abstract: Primary cultures of respiratory epithelium were produced as outgrowths from human fetal and adult tracheal and nasal polyp explants. Video recordings of the epithelial cell outgrowths were carried out after 5 days of culture and the ciliary beating frequency was analyzed by using a video technique. Uniform fields of differentiated ciliated cells were observed near the edge of the explant. In the transition region of the outgrowth from the explant to the outgrowth periphery, isolated ciliated cells were present, as well as cells with fused cilia. The ciliary beating frequency of the outgrowth of well-differentiated ciliated cells (13.5 ± 1.4…Hz) was significantly higher (p < 0.001) than the beating frequency of both the explant (11.9 ± 0.7 Hz) and the ciliated cells with fused cilia (9.8 ± 1.7 Hz). The same differentiation stages and functional activities were observed in the outgrowth cultures, whatever their origin. These in vitro models are comparable with each other and therefore could be useful for studying the ciliogenesis and functional activity of the human respiratory epithelium.
Keywords: Cell culture, tracheal outgrowth, nasal outgrowth, ciliary frequency
vol. 27, no. 3-4, pp. 559-565, 1990
Abstract: A new automated method of image analysis of sperm flagellar (human) and cilia (Dunaliella) bends is developed. This method permits an automatic determination of the line characterizing the flagellum. Two dynamic parameters are measured: the wave propagation velocity and the wave curvature radius. The data reveal similar patterns in the propagation of the principal and reverse waves between flagelated and ciliated cells. Conversely, differences are seen in principal wave curvature due perhaps to the presence of periaxonemal structures in the flagellum, absent in cilium. The identical patterns of reverse wave curvature in both systems may be linked to axonemal limitations.
Abstract: Plasma viscosity is elevated in various pathological states, due to increased levels of protein and other macromolecules. The possibility that elevation of extracellular fluid viscosity (EFV) affects cellular and biochemical functions was examined in cultured liver cells and in red blood cells. The viscosity was modified by the addition of various macromolecules, which differ in their capacity to increase viscosity and in their chemical nature. It was found that secretion of lipoproteins and lysosomal enzymes by liver cells is inhibited as a function of the medium viscosity. Correspondingly, elevation of plasma viscosity of hyperlipidemic rats reduced lipoprotein levels. In search…for the mechanism of this phenomenon we examined the effects of EFV on two cell membrane components which are involved in transmembrane processes: Gangliosides (GMs) , and phospholipase A2 (PLA2). It was found that the rate of GMs degradation is decreased with increasing EFV. Of special interest was the finding that the activity of cell membrane PLA2, a key enzyme in secretory processes, is inhibited by increasing EFV. This phenomena was not confined to cell membrane PLA2, as we further found that erythrocyte hemolysis, induced by soluble snake venom PLA2, is inhibited as the EFV is increased. It is proposed that the extracellular fluid viscosity may play an important role in regulation of cellular and biochemical processes in general.
Abstract: The effects of alterations in blood and plasma viscosities on plasma renin activity (PRA) were studied in dogs anesthetized with pentobarbital. Blood viscosity was altered by changing the hematocrit (Hct) level by isovolemic exchange using packed red blood cells or plasma. Plasma viscosity was elevated by isovolemic exchange using Hct-matched blood with high molecular weight dextran (Dx, mean m.w. ∼450,000) dissolved in plasma. Following control measurements of plasma and blood viscosities, plasma [Dx], PRA, Hct and hemodynamic functions, the dog was subjected to isovolemic exchange transfusions to either alter the Hct or administer the Dx. Various measurements were repeated 40–60…min after each exchange. Arterial pressure and renal blood flow remained relatively constant after exchanges; increases in plasma and blood viscosities were accompanied by a decrease in renal vascular hindrance (vasodilation) to keep the renal flow resistance at control level. PRA rose with increases in plasma [Dx] and viscosity, and the rise in PRA was best correlated with the decrease in renal hindrance. The changes in PRA and renal hindrance have the same regression line whether blood viscosity was altered by Hct variation or Dx administration. The results indicate that increases in viscosity cause a compensatory vasodilation of renal vessels to cause renin secretion.
Abstract: Investigations of Myoglobin, Hemoglobin and, more recently of Hemerythrin, suggest that the inward and outward motion of the oxygen ligand is governed by fluctuations between open and closed paths in the protein and that the driving force is the local brownian motion of protein residues. Reaction rates involving protein internal motions are strongly influenced by the viscosity of the sol vent, whereas the ultimate binding of oxygen at the protein’s active site remains viscosity independent. The description of a protein reaction therefore requires the introduction of a free energy surface with a conformation coordinate accounting for the viscosity-dependent protein transitions…in addition to the usual reaction coordinate which only describes the system of reactants in a fixed protein conformation.
Keywords: Hemoproteins, Hemerythrin, geminate recombinations, protein dynamics
vol. 27, no. 3-4, pp. 599-604, 1990
Abstract: Solvent viscosity is known to play an important role in the kinetics of biochemical reactions, and has been suggested to modulate the dynamic structure of proteins. The effect of viscous cosolvents, of various molecular sizes, on the apparent ultrasonic absorption of bovine serum albumin in solution, at 37°C, has been measured in attempt to investigate the following phenomena: 1) The predicted modulating effect of viscous cosolvents on the “internal friction” of proteins, and 2) possible differences between the microscopic and macroscopic pictures of the solvent viscosity concerning the proposed effect. We have found that A) The absorption of ultrasound (3–17…MHz) by the protein increases with increasing the cosolvent concentration. B) That increase correlates with the solvent viscosity for small cosolvent molecules, but not with macromolecular cosolvents, and C) Dextran solutions with the same concentration by weight, reveal similar ultrasonic absorption, in spite of large differences in their viscosity. A possible explanation is discussed.
Keywords: viscosity, mixed solvents, proteins, ultrasonic absorption, dextran, protein dynamics
vol. 27, no. 3-4, pp. 605-610, 1990