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Biodynamics: Circulation
The syringe was filled with 0.9% saline solution by adjusting the screw to allow the plunger to relax. The catheter was then fitted to the end of the syringe and the plunger depressed until slight inflation of the balloon was detected. The plunger was relaxed until the balloon was just deflated. This was repeated several times to remove any air bubbles from the balloon. The tip of the catheter was then placed in the epidural space of the spine. The balloon could then be inflated gradually by slowly injecting the desired amount of saline; the inflation could be held at any required level. Bipolar recordings of the potentials were obtained using needle electrodes anchored in the interspinous ligaments caudal to the vertebral processes. Responses were amplified 500 000 times, bandlimited to 10 Hz - 1 kHz and at least 2000 responses free of EMG or ECG artefact were ensemble averaged. A typical result is shown in Figure 3, from which it is apparent that cord compression produces changes in the evoked potential.
This research was supported by the Natural Sciences and Engineering Research Council of Canada. E. Morin R.N. Scott M. Olive PO Box 4400,
Bio-engineering Institute, University of New Brunswick Fredericton, NB, E3B 5A3 Canada
Bohlman, H.H. et al. Spinal cord monitoring of experimental incomplete cervical spinal cord injury, spine 198 1, 6, 428-436 Kojima, Y. et al. Evoked spinal potentials as a monitor of spinal cord viability, spine 1979, 4, 47 l-477 Cracco, R.Q. and Evans, B. Spinal evoked potential in the cat: effects of asphyxia, strychnine, cord section and compression, Electroenceph. Gin. Neurophysiol. 197 8, 44, 187-201 Uematsu, S. and Rocca, U. Effea of acute compression, hypoxia, hypothermia and hypovolemia on the evoked potentials of the spinal cord, Electromyogr. Clin. Neurophysiol. 1981, 21, 229-252
BlODYNAMICS:ClRCULATlON Y.C. Fung
Springer- Verlag, Berlin, FRG, 1984,404 pp $36.00 ISBN 3-540-90867-6 This book is part of a series, the first volume of which has previously appeared as ‘Biomechanics’. The present book is concerned with the mechanics of the circulation, and area in which Professor Fung has made notable and important contributions. The first chapter discusses the physical principles underlying any consideration of the circulation. The chapter, and its associated appendix, are both brief and will be inadequate for most readers. The author recognises that it will need to be extensively supplemented, and suggests reference to ‘Biomechanics’. The second chapter, dealing with the heart, opens the detailed discussion of the circulation. It starts simply with an account of the Windkessel model, and the stress distribution in the left ventricle. modelled as a thick walled hemispherical shell. These are followed by detailed, but largely qualitative, discussions of the geometry and materials of the heart, and aspects of electrical and mechanical events during the cardiac cycle. The treatment once again becomes more mathematical in the discussion of the fluid mechanics in the heart and stresses in the heart wall. The theoretical
development is never very extended, and it is unclear how well actual events are described by the models being discussed. The third chapter on blood flow in arteries is the longest in the book. It covers the subject in considerable depth, dealing with the effects of pulsatile flow and the geometrical non-uniformity and viscoelasticity of vessel walls, in addition to the simpler and more basic ideas of fluid flow in straight tubes. The chapter does tend to be a catalogue of work done rather than a critical appraisal, and this impression is further strengthened by the bibliography associated with the chapter which runs to more than 200 entries. The chapter on the veins is mainly concerned with the problem of elastic stability and flow in collapsible tubes, but also contains a brief account of pulmonary circulation. The chapter on the microcirculation describes the anatomy and the pressure distribution in the microcirculation. The mathematics in this chapter is largely concerned with flow at very low Reynolds numbers. There is also an extended discussion on model experiments on the interaction of leucocytes and the vascular endothelium.
J. Biomed.
Eng. 1986, Vol. 8, October
369
The final section brings together much of the contents of the previous chapters to discuss blood flow in the lungs. The chapter is technically complex, but it provides an unique overview of the subject, drawing very heavily on Fung’s own pioneering work. The book is not self-contained but will require to be supplemented especially for those with a limited mathematical competence. In addition, some of the background required to understand material in this book is covered in the previous volume. This volume is not easy to read, and the teleological approach used by the author can be somewhat diconcerting leadin , as it does, to his conviction that the presence o I; residual stresses in the heart
wall is an indication of optimum function. Teleological arguments and convictions of perfection are usually matters of opinion, not amenable to rigorous proof. Indeed they are really biotheology rather than biorheology. Nevertheless this is an extraordinarily valuable book. It is impossible to read without being stimulated by the author’s ideas. I would strongly recommend it as essential reading for all those who have a research interest in blood flow and the circulation. I am sure that for many of us it will not remain on the bookshelf but will be regularly read and re-read. J.C. Barbenel
BIOMATERIALS ORGANS
IN ARTIFICIAL
J.P. Paul, J.D.S. Gaylor, J.M. Courtney and T. Gilchrist MacMillan A-ess, Lik!, Londol?, UK and VCH Publkhm IC; Florida, USA UK and VCH PublishersInc, Florida, USA
CROYDON HEALTHAUTHORITY
SeniorElectra Medical Technician (Patient Services) To join a Team servicing Electra Medical equipment in Croydon District based at a modem wellequipped workshop at Mayday Hospital. You should hold O.N.C. (0.T.U) Cert. in Electronic Engineering or equivalent. Previous experience of fault finding and diagnosis desirable. Salary range f 7380/f experience.
9341
according to
Further information from Mr. R. Bain telephone
01 - 604 6999 ext. 3017. Application form and job description can be obtained from District Works Department, Queen’s Hospital, Queen’s Road, Croydon, 01-684 6999 ext. 4318.
Closing date for applications 10th October 1986.
The Strathclyde Bioengineering Seminars are well known for their review of a specific field with the invitation of leading researchers. The volume reviewed here contains the papers presented at the September 1983 seminar which addressed chemical, physical, medical and clinical aspects of biomaterials. It contains 38 papers resented at this meeting and the discussions held after each presentation. The majority of the contributions address biomaterials developments in the areas of haemodialysis, haemoperhision and plasmapheresis. About 12 papers address various aspects of softtissue replacement, and biocompatibility of surfaces. There is also one contribution on controlled release and one on bioceramics. All contributions are succinctly presented and contain much new information on fundamental research problems such as protein adsorption on polymeric surfaces, the fate of proteins in haemoperftrsion and dialysis, and the effect of flow conditions on the conformation of proteins. Some of the information of this volume has since been published in archival Journals but other papers present novel, yetunpublished techniques. The transcript of the discussions among authors and participants offers interesting viewpoints. Overall, this is a very good book which should be purchased predominantly by those who work on the clinical and medical side of biomaterials for artificial organs. N.A. Peppas
370
J_ Biomed. Eng. 1986, Vol. 8, October
This research was supported by the Natural Sciences and Engineering Research Council of Canada. E. Morin R.N. Scott M. Olive PO Box 4400,
Bio-engineering Institute, University of New Brunswick Fredericton, NB, E3B 5A3 Canada
Bohlman, H.H. et al. Spinal cord monitoring of experimental incomplete cervical spinal cord injury, spine 198 1, 6, 428-436 Kojima, Y. et al. Evoked spinal potentials as a monitor of spinal cord viability, spine 1979, 4, 47 l-477 Cracco, R.Q. and Evans, B. Spinal evoked potential in the cat: effects of asphyxia, strychnine, cord section and compression, Electroenceph. Gin. Neurophysiol. 197 8, 44, 187-201 Uematsu, S. and Rocca, U. Effea of acute compression, hypoxia, hypothermia and hypovolemia on the evoked potentials of the spinal cord, Electromyogr. Clin. Neurophysiol. 1981, 21, 229-252
BlODYNAMICS:ClRCULATlON Y.C. Fung
Springer- Verlag, Berlin, FRG, 1984,404 pp $36.00 ISBN 3-540-90867-6 This book is part of a series, the first volume of which has previously appeared as ‘Biomechanics’. The present book is concerned with the mechanics of the circulation, and area in which Professor Fung has made notable and important contributions. The first chapter discusses the physical principles underlying any consideration of the circulation. The chapter, and its associated appendix, are both brief and will be inadequate for most readers. The author recognises that it will need to be extensively supplemented, and suggests reference to ‘Biomechanics’. The second chapter, dealing with the heart, opens the detailed discussion of the circulation. It starts simply with an account of the Windkessel model, and the stress distribution in the left ventricle. modelled as a thick walled hemispherical shell. These are followed by detailed, but largely qualitative, discussions of the geometry and materials of the heart, and aspects of electrical and mechanical events during the cardiac cycle. The treatment once again becomes more mathematical in the discussion of the fluid mechanics in the heart and stresses in the heart wall. The theoretical
development is never very extended, and it is unclear how well actual events are described by the models being discussed. The third chapter on blood flow in arteries is the longest in the book. It covers the subject in considerable depth, dealing with the effects of pulsatile flow and the geometrical non-uniformity and viscoelasticity of vessel walls, in addition to the simpler and more basic ideas of fluid flow in straight tubes. The chapter does tend to be a catalogue of work done rather than a critical appraisal, and this impression is further strengthened by the bibliography associated with the chapter which runs to more than 200 entries. The chapter on the veins is mainly concerned with the problem of elastic stability and flow in collapsible tubes, but also contains a brief account of pulmonary circulation. The chapter on the microcirculation describes the anatomy and the pressure distribution in the microcirculation. The mathematics in this chapter is largely concerned with flow at very low Reynolds numbers. There is also an extended discussion on model experiments on the interaction of leucocytes and the vascular endothelium.
J. Biomed.
Eng. 1986, Vol. 8, October
369
The final section brings together much of the contents of the previous chapters to discuss blood flow in the lungs. The chapter is technically complex, but it provides an unique overview of the subject, drawing very heavily on Fung’s own pioneering work. The book is not self-contained but will require to be supplemented especially for those with a limited mathematical competence. In addition, some of the background required to understand material in this book is covered in the previous volume. This volume is not easy to read, and the teleological approach used by the author can be somewhat diconcerting leadin , as it does, to his conviction that the presence o I; residual stresses in the heart
wall is an indication of optimum function. Teleological arguments and convictions of perfection are usually matters of opinion, not amenable to rigorous proof. Indeed they are really biotheology rather than biorheology. Nevertheless this is an extraordinarily valuable book. It is impossible to read without being stimulated by the author’s ideas. I would strongly recommend it as essential reading for all those who have a research interest in blood flow and the circulation. I am sure that for many of us it will not remain on the bookshelf but will be regularly read and re-read. J.C. Barbenel
BIOMATERIALS ORGANS
IN ARTIFICIAL
J.P. Paul, J.D.S. Gaylor, J.M. Courtney and T. Gilchrist MacMillan A-ess, Lik!, Londol?, UK and VCH Publkhm IC; Florida, USA UK and VCH PublishersInc, Florida, USA
CROYDON HEALTHAUTHORITY
SeniorElectra Medical Technician (Patient Services) To join a Team servicing Electra Medical equipment in Croydon District based at a modem wellequipped workshop at Mayday Hospital. You should hold O.N.C. (0.T.U) Cert. in Electronic Engineering or equivalent. Previous experience of fault finding and diagnosis desirable. Salary range f 7380/f experience.
9341
according to
Further information from Mr. R. Bain telephone
01 - 604 6999 ext. 3017. Application form and job description can be obtained from District Works Department, Queen’s Hospital, Queen’s Road, Croydon, 01-684 6999 ext. 4318.
Closing date for applications 10th October 1986.
The Strathclyde Bioengineering Seminars are well known for their review of a specific field with the invitation of leading researchers. The volume reviewed here contains the papers presented at the September 1983 seminar which addressed chemical, physical, medical and clinical aspects of biomaterials. It contains 38 papers resented at this meeting and the discussions held after each presentation. The majority of the contributions address biomaterials developments in the areas of haemodialysis, haemoperhision and plasmapheresis. About 12 papers address various aspects of softtissue replacement, and biocompatibility of surfaces. There is also one contribution on controlled release and one on bioceramics. All contributions are succinctly presented and contain much new information on fundamental research problems such as protein adsorption on polymeric surfaces, the fate of proteins in haemoperftrsion and dialysis, and the effect of flow conditions on the conformation of proteins. Some of the information of this volume has since been published in archival Journals but other papers present novel, yetunpublished techniques. The transcript of the discussions among authors and participants offers interesting viewpoints. Overall, this is a very good book which should be purchased predominantly by those who work on the clinical and medical side of biomaterials for artificial organs. N.A. Peppas
370
J_ Biomed. Eng. 1986, Vol. 8, October