Understanding the Human Machine - A Primer for Bioengineering - Max E. Valentinuzzi

Chapter 8

Rounding Up and Looking Ahead

As already mentioned, “observe, think, and observe again”, used to say Dr. J.J. Izquierdo, an old well-reputed professor of physiology in Mexico back in the 1960’s ... and physiological signals are one way to observe; reading, interpreting and modeling those signals represent thinking about them, while modeling means also looking back to observe again, we may add. Finally, it is always good to round up and try to look ahead.

In this book we have underlined some historical aspects, including a few anecdotal pieces, because that kind of information often offers insights of the many components that may shape up the development of a given subject. We hope that objective was reasonably fulfilled and was enjoyable for the reader. Trying to look ahead is also a good exercise, although riskier for predictions may fail. Many subjects were consciously left out; otherwise, the book would have become too extensive and almost unreadable. Besides, we wanted to keep versatility and flexibility along with an agile rhythm.

There are areas that, without doubt, represent emerging and challenging fields, as adaptive control, micro and nano-technologies, which also relate to biomaterials, tissue engineering, cell engineering, biomedical implants and bones. Nano-technology is a rapidly growing field that will affect us all at some stage in our lives whether we know it or not. Intensive research is currently under way looking at ways in which our quality of life can be improved through the engineering of bone, tissue and organs. Some applications are currently available, as for example cochlear implants to restore hearing. More in the future are opto-retinal implants for the blind, artificial skin, tissue reconstruction, tissues and organs artificially grown on nano-patterned scaffolds. All this finds application in wound healing, regeneration of tissues and replacement of organs that have failed through disease or old age.

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Tissue engineering at the nano-scale level is leading to the development of viable substitutes, which can restore, maintain or improve the function of human tissues. Regenerating tissue can be achieved in several ways, e.g., by using biomaterials to convey signals to surrounding tissues to recruit cells that promote inherent regeneration or by using cells and a biomaterial scaffold to act as a framework for developing tissues. As an example, selected cells can be harvested from a patient and can be modified at the cellular level to prepare it for later transportation. Small biopsies from uninfected sites are used to isolate tissue specific cells which can then be encouraged to multiply. The cells can then be re-transplanted directly or are combined with an appropriate matrix for transplanting. A good source to consult is the special issue on this subject published by

IEEE Engineering in Medicine and Biology Magazine (vol 22, N°5, September/October, 2003).

The more we know about how cells work, the more possible it becomes to engineer cell to do things that once sounded like science fiction. This is cell engineering; in it, chemistry, nano-technology and materials science are all-important tools used to study and control how cells behave. One powerful way of finding out how cells work is by re-designing the extra-cellular matrix, the scaffold that surrounds a cell acting as a glue that sticks cells together. Cells react on the micro and nano-scale to the shape and chemistry of their surrounding environment. Nano-scale grooves, no wider then the cells themselves, can act as templates causing cells to line up. Once cells can be induced to organize themselves, even more possibilities open up, ranging from wound repair to the future vision of growing whole organs. Artery replacement is also possible using structures made form natural polymer to act as a scaffold around a patients natural artery, which given the appropriate stimulus, can be encouraged to regenerate. These scaffolds being biodegradable melt away after the regenerated artery is in place.

Implants have been traditionally used, say, in artery aneurisms, in dentistry, in vision to replace for example the lens, and in other medical applications. Countless patients have been benefited in the last three decades at least. The area is in constant expansion. A problem with medical implants is their acceptance by surrounding tissues. There are already specially developed coatings using nano-scale techniques and nano-

textured surfaces to create a cell friendly environment which encourages tissue to bond to the implant. Consequently, the implant will last longer and feel more comfortable.

Nano-technology can also take the potential for the rehabilitation of the infirm and elderly to a totally new domain. The domain of intelligent learning prosthetic devices. Some of the devices presently being researched include retinal implants. Many people suffer of degeneration of the retina with old age. One solution is to use a photo-sensor array which will detect incoming light and connect it to a signal processor. A signal can then be transmitted to an implanted receiver at the retinal interface which is connected via micro-contact to the retinal nerve.

In present day cochlear implants, the connection between the sound amplifier and the inner ear, consists of less than 22 electrodes which do not even make direct contact with the ganglions in the ear. Now, an implanted transducer can connect to one of the delicate bones in the inner ear, vibrating the bone to create sound

Bone supports our body as the hard main material of the skeleton. Nanotechnolgy is being used in teeth and bone replacements copying the way nature itself lays down minerals. This process is called biomimicry; it is already the basis of new tough and light materials for bullet proof vests and other defense applications. The use of nano-patterned polymers could eliminate the long recovery times, scarring and infection associated with bone grafts. Researchers hope to use this technique to grow adult stem cells that will turn into bone. Once the process of growing tissue on patterned scaffolding is perfected, nano-structured devices can be attached to further improve bone growth rates and reduce healing time. The devices have electrodes to provide an electric current which has been shown to stimulate bone growth as well as tiny channels along which controlled doses of the kind of proteins which have been shown to enhance cell growth can be pumped (see What is nanotechnology, CDROM prepared by the Institute of Nanotechnology, USA, or check its INTERNET site).

Bioinformatics is definitely on its way, including disciplines as biological structure informatics, computational biology, microarrays, genomic ontologies, genomics, neuroinformatics, pharmacogenomics and proteomics. Within bioinformatics we find also clinical informatics, with

clinical systems in high intensity care, disease management, e-health and clinical communication, evaluation of health information systems, health data warehousing, health information systems, integrated health and financial systems, patient records, public health informatics. Perhaps in this listing there is some overlapping, but time will certainly settle things down as experience and knowledge are gained.

Education and Training rises as an everlasting need, changing and evolving according to new technologies: Computer-assisted medical education, consumer health information, e-learning or distance learning, library information systems (especially under the pressure of the virtual journals), medical informatics teaching, patient education and self-care, nursing informatics, and professional education.

Human information processing and organizational behavior lead to subjects such as cognitive models, data visualization, natural language understanding and text generation, human factors and user interface, hu- man-computer interaction, models of social and organizational behavior, and natural language processing. Perhaps, some of these subjects fall somewhat outside the bioengineering range, but it happens that its reach is so wide and long that easily one finds invading other fields.

Imaging and signal analysis are permanent challenging needs. The image stands as the best means for conveying complex information because the eyes constitute the best input channel to the brain. Thus, image processing and transmission, image recognition, registration and segmentation methods, imaging and signal standards, knowledge representation and ontologies for imaging, model-based imaging, signal processing and transmission, virtual reality and active vision methods appear as wellneeded attractors for the creative minds.

Innovative technologies in health care include computer-communication infrastructures, mobile computing and communication, portable patient records, security and data protection, telemedicine, wireless applications and handheld devices. The subjects are obviously very pragmatic and medically oriented.

Finally, we should mention knowledge management which considers areas such as automated learning and discovery, clinical guidelines and protocols, controlled terminology, vocabularies and ontologies, intelli-

gent data analysis, decision support systems, neural network techniques, and pattern recognition and classification.

The list is long and very likely there are missing subjects or others that should not have been included. Ethics is the largest and most important; thus, the last paragraph is devoted to it (Valentinuzzi, 2004). What about the scientist’s ethics when involved in research and development of new weapons? Shall we follow the stand suggested by Tom Lehrer in the lyrics of his popular 1960’s song?

The rocket goes up, who knows where it comes down? That’s not my department, says Werner von Braun.

The XXth Century started with about 1,000 million inhabitants, the New XXIst Century is beginning with about 6,000 million people, and we know that before 2050 the number will climb up to may be 12,000 millions. Besides, in less than 30 years there will be severe limitations in the availability of fresh potable water. Science in general, technology, physiology and bioengineering in particular: what could they do or offer to solve or alleviate the pressures emerging from such demands? What can we, bioengineers, do to actually start a new beginning for human health? No doubt, hard and demanding is the challenge. Certainly, more and better weapons and more powerful armies are not the proper and sensible way. Perhaps, we had better remember that before anything else, we are simply men and women, that being is much better than having and that independently of how much richness, or power, or knowledge, or worldly glories we might collect and store, the really important and significant fact is and will be how much we love and how much we have loved. And the scientific endeavor calls for a lot of love.

My basic education —strongly founded in humanism— and graduate engineering formative years took place in Argentina. After working in telecommunications for 5 years, I went to the USA, where I spent 10 years and had the opportunity of studying and going into research. One of my daughters and her children live there. But I believed my possible modest contributions were more useful in my native country, a land so many times socially and economically stricken. Sometimes, when traveling through the Calchaqui Valleys route (Province of Tucumán, Argentina), at about 9,000 feet of altitude, I stop a few minutes to look at the children in that small Infiernillo Elementary School, isolated, surrounded

by winds and majestic silent huge mountains, far away from urban, selfish and arrogant centers, and ask to myself, what world and future do they face? Meanwhile, I admire the generous courage of their almost unsupported teachers. Certainly, if any of those children were to require, say, a cardiac pacemaker (a biomedical engineering product we are proud of), even the cheapest model would not be affordable for his/her family. How many children like them are there all over the world? Is that not our department? Think it over …

And this is all I have for the time being. I wish you enjoyed it and feel encouraged to proceed successfully in your career displaying a cheerful smiling face like these fellows below.

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