Upcoming conferences ( 3)

Swiss Society of Biomedical Enginnering (SSBE) annual meeting 2007 . (CSEM Neuchatel,Switzerland) ,september 13th and 14th. Deadline for abstracts: June 12th.

more information : http://www.ssbe.ch/2007_Meeting/

Complex biomedical devices; combining Pharma & medical technology

In the past, there used to be a quite distinct cut between medical devices and pharmaceutical products and intersection of devices and drugs occurred only at use. Examples of these kinds of medical devices are PCA pumps and imaging agents.

However, nowadays Drugs are added to devices to add value to medical devices and improve their function and efficiency. Moreover, sophisticated drug delivery systems integrate drugs and devices. We can mention transformal patches, coated catheters and drug eluting stents as some examples.

It is not really clearer if a combination of device-drug should be classified as a medical device or a pharmaceutical product. This becomes extremely important when it comes to regulatory affaires. Currently regulatory systems for pharmaceutical products and biomedical devices are totally different and not always really easy to handle for companies. Mostly this classification is claimed by the company and challenged by authorities. However, that may not end to a same classification in all the regions of the world. These kinds of Complex devices may be accepted in one region as a pharmaceutical product and in the other one as a biomedical device requiring two completely different procedure in the view of clinical trial and regulatory procedures. The problem may be much more important when it comes to devices combined with stem cells, tissue engineered materials and so on.

Deep Brain Stimulation

Deep Brain Stimulation (DBS), is currently used to treat the symptoms of Parkinson's Disease, essential tremor, dystonia, and other complex movement disorders and affective syndromes.
This process requires using different mechanical devices as well as image processing methods and micro drive mechanisms. Medtronics is one of the companies offering a solution for this intervention process. Take a look at their device Activa:
http://www.medtronic.com/physician/activa/

Physiome Project

Have you already heard of the Physiome Project? This is an idea to '' provide a computational framework for understanding human and other eukaryotic physiology. It aims to develop integrative models at all levels of biological organisation, from genes to the whole organism via gene regulatory networks, protein pathways, integrative cell function, and tissue and whole organ structure/function relations. ''

Although their website may not seem very interesting at the first look, you can find a lot of useful information in the ''Roadmap'' or through the review articles that you can find on the homepage. Take a look at it! The idea is great and they have some useful tools and databases to use as well. ENJOY!

Animal experiments, ethics and regulations

As a Biomedical Engineer, one may be involved up to certain levels in some animal experiments .This involvement can alter based on the nature of project. some may only work with data already obtained from in vivo or in vitro tests while others may have be in direct contact with animals.

I won't go through the question of if we have the right to perform animal experiments and to which extent. Here, I will consider readers, already in some degree of contact with animals and animal experiments.

In Switzerland, the animal experiments are allowed but under strict laws and regulation : Formative courses are done and regulations are checked continuously; research project which develop and use alternative methods to animal experiments are encouraged;principle of RRR (Reduction, Replacement and Refinement) are getting more and more recognized and so on.

However, I believe that finally, it is every single scientist that should be aware of ethics in this issue. This is not a simple subjects and there are several debates on it. I would suggest to keep your sensibility on the subject and Respect some ethical issues and while respecting animals.

for further information , check out:

Towards responsible animal research
Animal experiments in EC Legislation
UK legislation
Swiss Regulations
Animal welfare act and regulations in US

Complex Biomedical Devices and Immunoresponse of the body

One of the basic requirements of materials used in medical devices is their biocompatibiliy. They should not raise severe immunoresponses that can be hazardous for the patient or may alter the functionality of the device.

Biomedical devices are becoming more and more complex containing different combinations of drugs, biological and instrumental components. Recent studies shows while the effect of each combination may be known, the presence of them together, may lead to some unexpected complications.

Looking for more simple explanations?

Take a look at the following link of The Georgia Institute of Technology ,

http://www.gatech.edu/news-room/release.php?id=526

Soft tissue mechanics

Soft tissues are inhomogeneous, anisotropic materials which show viscoelastic and nonlinear properties. Morover, even under physiological conditions they undergo large deformations. For instance, in arteries, the in vivo longitudinal stretch ratio may pass more than 1.6. ( in vivo length/ unloaded length=1.6)

These properties make the continuum approach suitable for the purpose of analyzing material properties of soft tissue. Therefore, knowledge of nonlinear solid mechanics by a continuum approach seems essential.

Identification of an appropriate strain energy function (SEF) is the preferred method to describe the complex nonlinear elastic properties of vascular tissues. Once the strain energy function is known, the constitutive stress-strain relationships can be directly obtained from the SEF.

Early formulations of SEFs were purely phenomenological, in the sense that parameters involved in the mathematical expression of SEF bared little physiological meaning. Lately, significant effort has been put into developing structure-based or constituent-based SEF, where the parameters of the strain energy function represent some identifiable physical or structural characteristics of the different components of the vessel wall, such as elastic constants of elastin and collagen, fiber structural characteristics of the collagen network, volume fraction of elastin, collagen and vascular smooth muscle cells, etc.

An example of a constituent -based SEF which considers some structural properties, i.e. the orientation of the collagen fibers relative to the arterial wall’s circumferential direction is the model by Holzapfel and colleagues. The Holzapfel et al. model has been subsequently modified and extended by Zulliger et al. take the waviness of collagen fibers into the account and later to include vascular tone.

The structure-based SEFs did provide a significant improvement over the previous phenomenological SEFs. Furthermore, they supplied scientists more powerful tools to relate morpholoy with mechanical properties of soft tissue. Pa

CISM : international center for mechanical sciences

CISM, International Centre For Mechanical Sciences, offers different specialized courses in in interdisciplinary fields like robotics, biomechanics, environmental engineering and so on. I participated in the following summer course last year 2006 :

Biomechanical Modelling at the Molecular, Cellular and Tissue Levels

The course was really interesting and the organisation was very well-done. That was a really fantastic opportunity to encounter people working in this field and to discuss with the professors as well as the students and research people. Furthermore, Udine,the city in which the organisation is situated, is a really cute small Italian town close to Venice. If you have a chance to participate in one of the courses offered by CISM, don't hesitate to go.http://cism.it/

P.S. The picture shows the classroom.

Mechanobiology versus Biomechanics

I heard once these definitions from Prof. J.Humphrey and I find them quite nice :

Mechanobiology – the study of altered cellularactivity (gene expression or function) in response to changes in mechanical stimuli.

Biomechanics – the development, extension,and application of mechanics for purposes of understanding better biology, physiology, and pathophysiology as well as the treatment of disease and injury.(must invoke the 5 basic postulates of mechanics)

what I really like about the latter, is that mechanic laws should be extended and developed in order to be used in living tissue. We can not always use the existing rules. We should look for new ones, new relationships and discover new horizons. For sure, we have to remain in the framework of principle of mechanics.

up coming conferences (2)

European Symposium of Vascular Biomaterials(ESVB2007)
http://www.esvb.uha.fr/