Biorheology - Volume 19, issue 1-2

Article Type: Other

DOI: 10.3233/BIR-1982-191-201

Citation: Biorheology, vol. 19, no. 1-2, pp. ii-ii, 1982

Authors: Copley, Alfred L.

Article Type: Editorial

DOI: 10.3233/BIR-1982-191-202

Citation: Biorheology, vol. 19, no. 1-2, pp. 1-4, 1982

Authors: Fukada, Eiichi

Article Type: Meeting Report

DOI: 10.3233/BIR-1982-191-203

Citation: Biorheology, vol. 19, no. 1-2, pp. 5-10, 1982

Authors: Fukada, Eiichi | Mikamo, Yoshio | Takemi, Taro | Natori, Reiji

Article Type: Other

DOI: 10.3233/BIR-1982-191-204

Citation: Biorheology, vol. 19, no. 1-2, pp. 11-14, 1982

Authors: Fukada, Eiichi

Article Type: Research Article

Abstract: Electric polarization is important in various subjects in biorheology. Piezoelectricity, that is, stress- induced polarization and electric field-induced strain, is demonstrated in a variety of biological materials including polysaccharides, proteins and deoxyribonucleic acid. Complex piezoelectric constant depends on measuring frequency, temperature and water content. Piezo-electric relaxation is related to microscopic internal strain. Stress-induced potential in bone is produced by shear piezoelectricity in collagen fibers and/or streaming potential in canaliculate. The growth of bone is regulated to best resist external force. The controlling signal seems to be the electric potential. Application of small d.c. current or piezoelectric polymer film stimulates …the formation of bone in femur of animals. Various techniques of electrical stimulation are clinically used for healing bone fracture. Pulsing electromagnetic field enhances the proliferation of cell culture. Show more

DOI: 10.3233/BIR-1982-191-205

Citation: Biorheology, vol. 19, no. 1-2, pp. 15-27, 1982

Authors: Usami, Shunichi

Article Type: Research Article

Abstract: The apparent viscosity (η ) of blood is determined by plasma viscosity, hematocrit (Hct), cell deformation and cell aggregation. The optimum Hct for oxygen transport varies with shear conditions and shows regional differences. In circulation in vivo , the complex geometry causes inertial, in addition to viscous, losses. Microvessels have low Hct and correspondingly low η . Hydrodynamic interactions between red blood cells (RBCs) and white blood cells (WBCs) may contribute to WBC adhesion to the endothelium. Entry of WBC into diverging branches may cause redistribution of RBCs. There is some understanding of the relation between in vitro and …in vivo blood rheology, but further investigations are needed. Show more

Keywords: Aggregation, Capillary, O2 delivery, Deformation, Leukocytes, Viscosity

DOI: 10.3233/BIR-1982-191-206

Citation: Biorheology, vol. 19, no. 1-2, pp. 29-46, 1982

Authors: Copley, Alfred L.

Article Type: Research Article

Abstract: 1. Introductory Remarks 48 2. On the Scope of Biorheological Inquiry 49 3. Biorheology - The Missing Link in the Life Sciences 49 4. Macro-Biorheology 50 5. The Vessel-Blood Organ 50 6. Electro–Biorheology 51 7. Connective Tissues 51 8. Muscle Contraction 53 9. Carnivorous Plants 53 10. On the Worthiness in Studying Rare Biorheological Phenomena 54 11. Mobility of Spermatozoa 54 12. Ribosomes, Protein Synthesis and Protein Kinases 54 13. Enzymes and Conformational Changes 55 14. Leukocyte Migration 55 15. Multienzyme Systems 55 16. Cytoplasmic …Streaming, Ciliary Motion, Cell Motility, Cell Shape Changes 55 17. Microtubules and Motility 56 18. Transport in Nerve Cells 57 19. Motion of Chromosomes and Pigment 57 20. Actin and Myosin 58 21. Action of Carriers and Channels in Biomembranes 58 22. Surface Hemorheology 58 23. Conformational Changes in Biological Macromolecules 59 24. Quantum Biorheology 60 25. Hormones, Peptide Hormones, Mobile Hormonal Receptors 60 26. Communication Theory in Biorheology and Other Points 61 27. New Methods, Instrumentation and Techniques 61 28. Clinical Biorheology 62 29. Organizational Aspects of Biorheology as a Science 62 30. Bio-Ethical Problems 63 31. The Individual Scientist and the Socratic Distinction 63 32. A poem by Parmenides 63 33. Conclusion 64 34. References 64 Show more

DOI: 10.3233/BIR-1982-191-207

Citation: Biorheology, vol. 19, no. 1-2, pp. 47-69, 1982

Authors: Hiramoto, Y.

Article Type: Research Article

Abstract: Mechanical properties of the cell before and during cleavage in sea urchin eggs (a typical equal symmetrical cytoplasmic division) and polar-body formation (a typical unequal cytoplasmic division) are reviewed with special reference to the mechanism of cell division. Both in sea urchin eggs and starfish oocytes, the tension at the cell surface gradually increases before the onset of cytoplasmic division. The tension gradually decreases during division in starfish oocytes and in some sea urchin eggs. Some other sea urchin eggs display two peaks of the tension, one just before the onset of division and the other during division. The cleavage …furrow is formed by the active contraction of a layer formed in the equatorial cortex of the cell in sea urchin eggs and of a ring-shaped layer formed in the cortex around the animal pole of the cell in starfish oocyte. Show more

Keywords: Cell division, mechanical properties of protoplasm, sea urchin eggs, starfish oocytes

DOI: 10.3233/BIR-1982-191-208

Citation: Biorheology, vol. 19, no. 1-2, pp. 71-78, 1982

Authors: Fung, Yuan-Cheng

Article Type: Research Article

Abstract: The pulmonary capillary blood vessels have a unique planar sheet-like geometry with thickness about the same as the diameter of the red cells. The hemorheological properties of the blood in such a network is dominated by the interaction between the red cells and the capillary vessel wall. A distinctive feature of the blood flow in pulmonary capillaries is the non-uniformity in the distribution of red blood cells in the alveolar walls. To explain this nonuniformity, we showed that in branching capillaries the hematocrit distribution depends on the velocity distribution. If a vessel bifurcates and if the velocities in the daughter …branches are unequal, then the faster side gets more red cells. If the velocity ratio exceeds certain critical value about 2.5 (with exact value depending on cell rigidity, tube diameter and hematocrit), then the slower branch gets no red cell at all, (i.e. hematocrit → 0). Another reason for the nonuniform hematocrit distribution is due to occasional plugging of small blood vessels by leukocytes. The force of interaction between leukocytes and the vascular enothelium is determined. Turning to the blood flow, we show that it is affected critically by the elasticity of the blood vessels. In recent years we measured the distensibility of pulmonary capillaries and arterioles or venules of the cat by the polymer casts method, and arteries and veins of diameter 100 μ m and up by the x-ray method. Thus the elasticity of all blood vessels of the cat’s lung is now determined. With this information the nonlinear pressure and flow relationship is determined. Furthermore, we have shown that all pulmonary veins, including the venules, remain patent (not collapsed) under negative transmural pressure as large as −17 cm H2 O. This important fact tells us that in the sluicing condition of zone 2 (where the pulmonary venous pressure is lower than the alveolar gas pressure), the sluicing gate must be located at the exit ends of the alveolar capillary sheets. With this information the flow limitation problem is solved. Show more

Keywords: Pulmonary blood flow, Hematocrit distribution

DOI: 10.3233/BIR-1982-191-209

Citation: Biorheology, vol. 19, no. 1-2, pp. 79-94, 1982

Authors: Stehbens, W.E.

Article Type: Research Article

Abstract: Atherosclerosis is an ubiquitous disease effecting degenerative, proliferative and atrophic changes in the vessel wall. Preoccupation with intramural lipid accumulation has been at the expense of studies concerning other aspects of atherosclerosis including the complications. The current view of the lipid hypothesis fails to explain the localization or the complications. They can be accounted for by the thesis that atherosclerosis is due to hemodynamically-induced engineering fatigue. In animal models, in which gross disturbances of flow occur, the disease morphologically similar to atherosclerosis in man, together with the complications, can be reproduced at an accelerated rate, thus substantiating the fatigue hypothesis. …Moreover, hemodynamics appears to govern dietary-induced lipid accumulation, but these two factors acting in concert will not reproduce atherosclerosis as it occurs in man. Show more

Keywords: Hemodynamics, Atherosclerosis, Fatigue, Arteriovenous Fistulas, Aneurysms, Complications

DOI: 10.3233/BIR-1982-191-210

Citation: Biorheology, vol. 19, no. 1-2, pp. 95-101, 1982