WALT - World Association of Laser Therapy

WALT Review

Issue 1 2009

Editor: Jan Tunér, This e-mail address is being protected from spam bots, you need JavaScript enabled to view it

Welcome to 2009 and the first edition of WALT Review, an expanded version of our eNewsletter, which has been published since 2000. Our new electronic publication will bring you articles, news, debates and interviews. This first edition will be available publicly on our web site, but in the future you will receive an email informing you about a new issue. You can then read it in the membership area on our web site. So keep your log in data at hand. If you have lost your log in data, send an email to This e-mail address is being protected from spam bots, you need JavaScript enabled to view it . All previous eNewsletter are available in the membership area.

Editorial: What’s in a name?

The confusion about the ”correct” terminology for laser therapy is a never ending story. How many names do you know? Five or ten? The term “laser therapy” that I am using now is in itself inappropriate, because if you go to PubMed and search using that term, you will have hits on a couple of thousand surgical papers. And if PubMed doesn’t accept a term used as key word, then you will not find that paper in that important system.

The terms accepted on PubMed/Medline and others are decided by MeSH - National Library of Medicine - Medical Subject Headings, found on

http://www.nlm.nih.gov/cgi/mesh/2002/MB_cgi?term=LASER+THERAPY,+LOW-LEVEL

The accepted terms are:

LLLT, Laser Biostimulation, Laser Irradiation, Low-Power, Laser Therapy, Low-Power, Low-Level Laser Therapy, Low-Power Laser Irradiation, Low-Power Laser Therapy

If a different key word is used, you will not find it on PubMed. So whatever suggestions we may have, MeSH must be included in the discussion.

All the suggested names have pros and contras. The most recent suggestion is Laser Phototherapy. It is a distinct description and the terminology can be expanded to LED phototherapy, Polarized light phototherapy etc. But, not being accepted yet by MeSH, it cannot be used as a key word in scientific papers.

The situation continues to be confusing and unfortunately the specialized laser papers contribute to the terminology chaos. In these journals you can find different terms in different papers and in some cases even within the same paper. A minimum demand should be that these journals decide on one, whichever, terminology and try to stick to it until consensus is reached.

Another thing about MeSH – this is the definition found:

Treatment using irradiation with light at low power intensities and with wavelengths in the range 540nm-830nm. The effects are thought to be mediated by a photochemical reaction that alters CELL MEMBRANE PERMEABILITY, leading to increased mRNA synthesis and CELL PROLIFERATION. The effects are not due to heat, as in LASER SURGERY. Low-level laser therapy has been used in general medicine, veterinary medicine, and dentistry for a wide variety of conditions, but most frequently for wound healing and pain control.

Not a bad description, but to stop at 830 nm is certainly not correct. Laser stimulation has been documented even with CO2 lasers, i.e. a wavelength above 10 000 nm. A minimum requirement would extend the wavelength range to 980 nm.

WALT is, for the time being, not favoring any particular terminology, only consistency.

Ed.

We have a new president

The new president of WALT is Professor Jan M Bjordal of Bergen, Norway. Professor Bjordal has been the scientific secretary of our association for four years and has been very active in research, frequently in cooperation with Brazilian researchers. Among his valuable contributions to the progress of LLLT is his ability to analyze the literature, pinpointing the flaws in negative studies and finding the optimal dosage windows for different conditions. The photo below depicts the General Secretary Antonio Pinheiro congratulating the newly elected president.

Jan Bjordal is keeping a close watch on the published literature and has been keeping track of the LLLT material published on PubMed after the year 2000. The table below is a fine illustration of the growth of laser therapy.

The interview: Professor Tiina Karu

I know that biostimulative lasers were much more in use in your country already when you were a student, but still, as a biologist, how come you got involved in this field?

First of all, I am not biologist. I am physical chemist by my university education and turned my face to biology and medical problems step by step during years. This circumstance has its pluses and minuses. Right now I think that my educational background helped me a lot for better understanding the problems of such a multidisciplinary science as the interaction of laser radiation with cells and organisms is. The first step to get familiar with cellular metabolism was my Ph.D. student time, when I worked in the field of chemical carcinogenesis. My second degree, Dr. Sci., was fully devoted to the problems of laser light-cells interactions. I have to recall that the highest degree of Doctor of Sciences in former USSR and now in Russia does not have its counterpart in Western countries; one can probably compare it with Doctor of Habilitation in Germany. Without that degree, one can not get the professorship, for example. The PhD’s counterpart by the scientific level in Russia is called Candidate of Sciences.

In the 80s and early 90s few Russian laser research reports were available in English language journals and therefore not available to non-Russian speaking readers. But you were early in publishing in English. What made you take this step?

Yes, the laser biostimulation community in USSR was active and rather large. One can read about this in more details in Lecture 2 of my last book. This circumstance was connected with fast and strong development of lasers by academical and industrial institutions with wishes to spread this production in as many as possible practical fields, incl. agriculture and medicine. This circumstance created the following situation: in the field of laser biostimulation people worked with physical, technical and medical background but very few biologists were involved. It is seen in history that such an approach worked well when the damaging action of “strong” factors (powerful laser beams as well as y-rays, x-rays, UV radiation) on cells and organisms were studied. In case of investigating the action mechanisms of such a “weak” factor as visible laser light, this approach did not work so productive. Another reason why there are still not so many biologists in the field of laser biostimulation is the following: for a long time, and even now most photobiologists solemnly believe that only UV radiation acts on the cells, but visible and near IR parts of solar spectrum are involved only into photosynthesis, photomorphogenesis, phototaxis etc. and do not influence the metabolism of nonphotosynthetic cells. Last years the situation is improving but very slowly.

Your statement that “in the 80s and 90s few Russian laser research reports were available in English …” is not fully right. They were available and Western laser physicists read them because Soviet laser science was in leading positions in the world. Biologists and medical doctors read these articles very rarely. All important Russian journals were translated from cover-to-cover into English. I have seen those bookshelves in all libraries of leading US universities. Laser specialists in US and Europe studied the Russian quantum electronics literature very carefully via these translations. But among this group of active leaders of laser physics very few were interested in medical applications of lasers. I have seen this on the example of my first (and basic) publications in Soviet J. of Quantum Electronics (the cover-to-cover translation of Kvantovaya Electronika, the most important Russian journal in this field). By the way, the situation was similar in case of English language physical journals like Il Nuovo Cimento published in Italy. Biologists and medical doctors did not read them. Taking together, I just think that in 60ties, 70ties and 80ties there was no real scientific demand for an appearance of “healing laser therapy”. Surgical laser applications found their niche in medicine and that was enough at that moment. May be now the time for (laser) light biostimulation has come, who knows?

Summing up, the exact and short answer to your question is the following: I tried to publish in English as much as possible with the hope that sometimes somewhere somebody will find this topic interesting to study and use.

Your husband Vladilen Letokhov is one of the leading physicists of Russia. I suppose his knowledge of physics has been an asset in your research?

Vladilen’s influence on my understanding of principles how the science is built up has been tremendous. His unique type of thinking, his creative aura, his stile of working and communication with other scientists is unique. I have had the privilege to have some fast home lections when I did not know how to solve this or that arising problem. On the other hand, he was always rather critical and sharp in his opinions. That was not encouraging at the first moment but later I understood how helpful this approach was.

Although lasers were used more extensively in Russia when you initiated your work, did you experience any of the skepticism that LLLT was suffering from in “the West”?

I answered partly this question already. First, some word about skepticism. Most skeptical were theRussian laser producers. At that time when I entered the field of laser biostimulation, clinics and policlinics in USSR were well equipped with He-Ne lasers and of course their producers did not want to hear that the same “things” can be done by noncoherent light as well. I always emphasized that the He-Ne lasers are very useful for medical treatments but beam’s action mechanism on cells is principally the same as in case of noncoherent beam with the same parameters (first of all intensity, dose, wavelength). This problem was finally solved when LED’s appeared and these were used with the same success as lasers. A similar situation appeared in West as well. For example, as many of us do remember, in the 80ties the world was full of Space lasers. The company organized conferences and every kind of promotion and the medical doctors were sure that this is the best equipment to solve all their problems. Here I would like to emphasize that lasers are excellent for irradiation but the action mechanism can not be explained only by some particular properties of its radiation. Taking together, strong commercial interests are not the best to solve a scientific problem. This happens, however, quite often and not only in our field.

Now some words about the attitude of world leading laser medicine laboratories to laser biostimulation. In the second half of 80ties I got the invitations to give lectures in all these laboratories situated in U.S. and also gave the quest lecture in Gordon Conference “Lasers in Medicine” in 1988. Recall that Gordon Conferences is a special type of conferences organized on various scientific topics for exchange of ideas and opinions. Recordings are prohibited. Also, my invited review papers appeared in “IEEE J. of Quantum Electronics” and “Health Physics” (both these journals are printed in US). At that time, the hot topics in laser medicine were plaque ablation of blood vessels and a search for biological use of free electron lasers. These two topics plus photodynamic therapy and studies into ocular damages by laser beams got prevailing part of funds. It took almost 10 years when it appeared that the first two of these fields were dead ends. Nowadays, in some of U.S. leading laser medical labs one can notice some experimental activity. The work of Dr. M. Hamblin at Wellman Labs in Boston for example. There are active groups near Washington DC (Dr. J. Anders and Dr. R. Waynant) and in Wisconsin (Dr. M. Wong-Riley and Dr. J. Eells). All these groups work on a very high experimental level. Let us hope that this is a beginning to fill the gap between the work of laser specialists who develop the equipment and medical doctors who use the lasers and LED’s.

You are working in a famous laboratory in Troitsk, not far from Moscow. So much work on the cellular effects of laser light has emanated from this place. Could you tell us a bit about this institution?

My institute was established in 1979 as Laser Technology Research Center of Acad. Sci. USSR and later renamed to the Institute of Laser and Information Technologies of Russian Acad. Sci. I was elected to be the head of the Laboratory on Laser Technology of Complex Molecules in 1980 and I was free to choose the problems and hire the staff. Later, our laboratory was renamed to Laboratory of Laser Biology and Medicine. Everything was new - the institute, people, problems. During years, I have been in close contact with Institute of Spectroscopy of Russian Acad. Sci. as well as with some biological – medical institutions in Moscow: N.N. Blokhin Cancer Research Center of Russian Acad. of Medical Sci., Institute of Molecular Biology of Russian Acad. Sci., Institute of Microbiology of Russian Acad. Sci.

There was an interesting situation in science in Soviet times. Similar situation could be created only in conditions of strongly planned for years beforehand science and economy, but not in conditions when short–time grants are provided to solve a certain problem. At these Soviet times of planned economy, all laboratories had enough money and equipment and it was rather easy to cooperate for solving together some not planned tasks when you got the people interested in it. I should be emphasizing that most Soviet scientists were extremely enthusiasts in their fields. It was possible and creative to discuss new ideas generated by the labs in one field, in the labs of different fields. This was in 80ties a productive way to work in the new field of laser biology. The situation is different now, i.e., it is very close to the sitation in West, where everybody in strictly connected with the particular grants.

There must have been many “aha” experiences during all these experiments. Can you mention a few of the most important ones?

Practically all of the experimental results were fascinating for us. Interesting thing is that some results, which were considered as exiting ones for us, did not interest the readers or listeners. And vice versa, some rather expected findings got unusual attention.

You have published three books in English; the most recent one is “Ten Lectures on Basic Science of Laser Phototherapy”. What made you decide on this didactic approach?

The reason is the real complexity of the material. I have seen during my lectures that the listeners often did not follow simple connections, in my opinion, and they were not able to follow the reason – result connections. When planning this new book, I looked at our home bookshelves and recognized that some physicists have published their new research and ideas in the form of lectures. So I got the idea to try this with my complex material as well.

You and your husband are now living part time in southern Sweden, how come?

Vladilen was elected as the Tage Erlander Quest Professor for the year 2000. The Tage Erlander Quest Professorship gives to the internationally eminent foreign researchers the opportunity to spend a year at a university, other higher education institution or research institute in Sweden. The Professorship was set up by the Riksdag (Swedish Parliament) in 1981 to honor of Tage Erlander, the former Prime Minister, on his 80th birthday. The subject field of the appointee (one per year) to the Professorship varies, and during Tage Erlander’s lifetime the nomination took place in consultation with him. The appointment normally lasts for one year, and the holder is selected by invitation from the Swedish Research Counsel. As far as we were not able to be away from our labs for one year, Vladilen used his grant during some years, every year for several months. Later, Nobel Foundation and Wenner-Gren Foundation supported his research in Lund is this field.

Vladilen decided to work at Lund University on the problem of laser effects in astronomy. In 1972, he has proposed that laser effects can appear also in the stellar atmosphere, i.e., in natural conditions. At that time, no possibilities to check this idea existed. Nowadays the spectra recorded by Hubble space telescope enabled to do this work. During the years 2000-2008 Prof. Vladilen Letokhov and Prof. Sveneric Johannson have discovered and fully described this phenomenon. Their book about “Astrophysical Lasers” is published by Oxford University Press in 2009. So, instead of one year we have been in Sweden time-to-time during 8 years and have even a household in the little village of Bjärred between Lund and Malmö. I have used my time in Sweden to write and think about scientific problems and last but not least, my most recent book was written in Bjärred as well.

In the next issue: The lion and the laser – another interview. lion and the laser – another interview.

Introducing: Rodrigo Alvaro B. Lopes Martins

Rodrigo Lopes- Martins is the new acting Scientific Secretary to WALT, taking over the duties of President Jan M. Bjordal during his presidency. Dr. Lopes-Martins is one of the most active laser therapy researchers in the world. He is trained as a pharmacologist and he has been active in WALT for the last 4-5 years. He finished his PhD in 1998 at University of Campinas, Brazil, and he is currently leading the laser research group at the Pharmacology Department at University of Sao Paulo, Brazil. During the last 5 years, he has contributed to no less than 19 Medline-indexed laser publications. We welcome onboard Dr. Lopes- Martins ,and we are very happy that he will dedicate his efforts to WALT for the coming period.

Scientific Secretary’s Report 2008

A detailed report from the Scientific Secretary can be found at http://www.walt.nu/scientific-secretary-report/index.php. The 904 nm dosage recommendations at http://www.walt.nu/dosage- recommendations.html have been slightly updated, based upon new research.

WALT2008 awards

Four awards for Best Presentation were presented at the WALT2008 congress. The winners were:

• Roberta Chow, Basic science award
• Shimon Rochkind, Clinical science award
• Denise Hawkins Evans, Young investigator award (Heidi Abrahamse group)
• Diane Meneguzzi, Young investigator award (Rodrigo Lopes-Martins group)

The difficult parameters

For many years WALT has been engaged in spreading information about the very important but so difficult issue how to calculate a certain dosage and how to report on all the laser parameters, in order to make a control calculation possible. The following is an excerpt from an Internet discussion related to this subject. First, Peter Jenkins has reacted on the vague dosage reporting in a study and closely analysed what may have been, compared to what is actually reported. It is a bit complicated, but you can learn a lot by reading it attentively.

An analysis and review of the laser and dose parameters stated in Yeldan et al, 2008 “The effectiveness of low-level laser therapy on shoulder function in subacromial impingement syndrome”.

The conclusion drawn by the authors of this paper is that “…there is no fundamental difference between LLLT and placebo LLLT when they are supplementing an exercise programme for rehabilitation of patients with shoulder impingement syndrome.”. As has been shown many times, dose is often the confounding factor in treatment efficacy, with a prevalent cause of negative outcomes being doses that are too low. To provide both a clinical and scientific guide, the World Association for Laser Therapy (WALT) published dose recommendations for a number of conditions, for both continuous wave (780-860nm) and super-pulsed (904nm) lasers, which are freely available for download from the WALT website. http://www.walt.nu/dosage-recommendations.html.

Before addressing whether the dose used in this study is within the range recommended by WALT, I looked at the laser parameters to see if the reported dose is accurate. Doing so, however, was not as straightforward as it should be...
The information provided by the authors about the actual laser parameters was less than desirable, as it was quite clear from the outset that further data from the manufacturer and additional calculation would be required to obtain sufficient parameters to assess the accuracy of the reported dose.
Summarising the authors' description of the treatment protocol and parameters, we get the following information:

Treatment Protocol:

• Dose per Point: 3 Joules
• Time per Point: 90 seconds
• Number of Points: 5 (maximum)
• Treatment Duration: ~8 minutes (total)

Laser Parameters:

• Laser Type: GaAs
• Operating Frequency: 2000 Hertz
• Operating Wavelength: 904 nanometers

In the paper, the device used in the study is described simply as the "Roland Serie Elettronica Pagani, wavelength 904 nm, frequency range of 5-7000 Hz and maximum peak power of 27, 50 or 27x4 W".
This incomplete description leaves the reader with no specific information about the actual peak power or average power of the laser device used in the study, and so we're given insufficient detail with which to double-check the stated dose parameters. After looking at the various lasers available from 'Elettronica Pagani' under the 'Roland Series' name, I was able to ascertain that the device used was the 'Bassa Potenza IR 27' . It's description, translated from the original Italian on the manufacturer's website using Google's language tools, is: LASER IR27: …is equipped with a diode operating at a wavelength of 905 nm, a frequency adjustable from 5 to 7,000 Hz and a power ranging from 27 Wp - 100 Wp (equivalent to 25 - 90 mW).

They also list three applicators:

• 27 Wp
• 48 Wp
• 4x 27 Wp

As used here, 'Wp' is a shortened form of 'Watts Peak', or Peak Power in Watts.
(Note: There are some slight discrepancies in the information provided by the authors of the paper and that on the manufacturer's website, but these do not affect the conclusions of this review.) Although the manufacturer’s information is somewhat useful (you'll see why later), we are currently no closer to knowing, specifically, what the peak power or average power were that were used in the study. We now need to deconstruct the dose information provided in the paper, and then cross-reference it against the stated laser parameters and the manufacturer's data, to see firstly whether the claimed dose parameters are accurate. Then, we'll need to compare the actual dose parameters, or as close as we can get to them, with the WALT recommendations.

The manufacturer provides us with a couple of pieces of information which are not, in and of themselves, particularly enlightening, but they are useful in that they provide a link between Peak Power and Average Power that we can use to deconstruct and reconstruct other parameters:

"…power ranging from 27 Wp to 100 Wp (equivalent to 25 - 90 mW)"

This gives us a starting point for our investigations, as follows:
GaAS laser diodes are always operated in pulsed mode, in that they emit a series of very high power but very short duration pulses which are repeated over time. The average power of most GaAs-based pulsed laser systems is, therefore, a function of the peak power and duration of each pulse, and the number of pulses per second:

Average Power (W) = Peak Power (W) x Pulse Duration (s) x Frequency (Hz)

I think we can safely assume that the manufacturer has followed industry norms and stated the maximum achievable Average Power for each given Peak Power. As we can quickly see from the equation above, the highest Average Power will be achieved at the highest frequency, which is stated to be 7000Hz. So now we know, with a reasonable level of certainty, the Peak Power, the Average Power and the Frequency. What we don't know is the Pulse Duration, so we need to play around with our equation and work it out. Using the applicator with a peak power of 27W and an average power of 25mW (0.025W) at 7000Hz:

Pulse Duration (s) = Average Power (W) / (Peak Power (W) x Frequency (Hz))
PD (s) = 0.025W / (27W x 7000Hz)
PD = 0.025 / 189,000
PD = 0.000000132 seconds (132 nanoseconds)

Ok, what does this tell us? Nothing! …Yet.
Let’s now look at the applicator with a peak power of 48W, and see what the average power at 7000Hz will be with a pulse duration of 132 nsec:

Average Power (W) = Peak Power (W) x Pulse Duration (s) x Frequency (Hz)
Average Power (W) = 48 x 0.000000132 x 7000
Average Power (W) = 0.044352 (44.352 mW)

For brevity, I’ll assume that the 4x27W applicator has an average power per diode the same as the single-diode 27W applicator, which is 25mW. If we now go back to the paper, and consider the authors’ stated treatment parameters, we can compare the various applicators to see which one was used in the study. Again, here is the summary:

Treatment Protocol:

• Dose per Point: 3 Joules
• Time per Point: 90 seconds
• Number of Points: 5 (maximum)
• Treatment Duration: ~8 minutes (total)

Laser Parameters:

• Laser Type: GaAs
• Operating Frequency: 2000 Hertz
• Operating Wavelength: 904 nanometers

The key parameters here are the dose per point, the irradiation time per point, and the operating frequency. We know that dose is equal to the average output power of the laser multiplied by the irradiation time:

Dose (Joules) = Power (Watts) x Time (seconds)

So, by taking the dose and irradiation time per point and transposing the dose equation, we can quickly work out what the average output power of the laser must be in order to deliver the given dose in the given time:

Power (Watts) = Dose (Joules) / Time (seconds)
Power (Watts) = 3 / 90
Power (Watts) = 0.033r (or 33mW)

OK, we now know that, if the authors’ dose calculations were correct, the average output power of the laser used in the study was 33 mW at 2000Hz. Let’s see if any of the manufacturer’s applicators are a match, by using the average power equation described earlier and factoring in what we already know about the manufacturer’s three different applicators:

Average Power (W) = Peak Power (W) x Pulse Duration (s) x Frequency (Hz)

So,

Applicator 1: 27 Wp Average Power
Applicator 1 (W) = 27 x 0.000000132 x 2000 = 0.007128
Applicator 2: 48 Wp
Average Power Applicator 2 (W) = 48 x 0.000000132 x 2000 = 0.012672
Applicator 3: 4x 27 Wp
Average Power Applicator 3 (W) = 4 x 0.007128 = 0.028512

As we can see, none of the three applicators emits 33mW of power – either per diode or in total – and so none will accurately deliver 3 Joules in 90 seconds.
That means either one of two things:

1.  The applicator used in the study was non-standard; or
2. The dose as stated in the published paper is incorrect.

However, perhaps we can assume that, as it is the closest in total power to that required, the 4x27W probe was used?
First, it is important to note that it is highly inaccurate to use the total power of a multi-diode laser applicator when calculating the dose per point. However, if we assume for the time being that this is what the authors have done, the total dose delivered during the 90 second irradiation time would be approximately 2.6 Joules, not 3 Joules as stated by the authors, and it would actually be distributed as 0.64 Joules per point over 4 points.

Looking at the WALT-recommended doses for the treatment of other anatomical sites, we can see that minimum doses range from 1 Joule per point (lateral epicondylitis) to 10 Joules per point for arthritis of the lower spine or hip. Although there are no dosages recommended by WALT specifically for treating subacromial impingement syndrome, the minimum recommended anti-inflammatory dose for the treatment of acromio-clavicular arthritis with a 904nm GaAs laser is 2 Joules per point. Further, 2 Joules per point is recommended for most of the listed tendinopathies.

Therefore, I believe it is reasonable to assume that 2 Joules per point closely approximates the minimum dose required for the treatment of subacromial impingement syndrome.

As we’ve seen, above, the 4x27W applicator – the only one which can deliver a total dose close to the stated 3 Joules in 90 seconds – will only actually deliver 0.64 Joules per point (2.6 Joules total) in that time.

So, without the benefit of a more accurate and complete description of the laser parameters used in this study, one could reasonably conclude that the lack of efficacy found is due to the applied dose being too low. That said, one must also realise that this conclusion is based upon insufficient information and, so, may be wildly inaccurate in itself. The major flaws in this paper are the lack of accurate reporting of the laser power, preferably as verified by an independent tester, and the inclusion of a very vague and imprecise description of the laser device itself, which combine to ensure that this study cannot, with any certainty, be reproduced.

So where does that leave us? In my opinion, it leaves us with another scientific paper that, due to the incomplete and possibly inaccurate reporting of laser parameters, adds little or no value to the overall body of knowledge about laser therapy and should not have been approved for publication in its current form.

Jan Bjordal adds his comment:

Dave Baxter and I commented upon this laser in a response to the Bingol shoulder paper, and the authors` response revealed that neither the authors nor the manufacturer knew the mean output of the laser. We have just managed to find a unit and test the laser from Roland Pagani Elettronica. Contrary to other lasers, the problem here is that the laser has a mega-sized convex lens of about 18 cm2 spot area. So the four laser diode beams are distributed over this area. Contrary to the other lasers used for tendinopathies the problem here is that we have a too large spot size and too low power density. With such a large spot size You also have a large problem with reflection when applied to the anterior upper part of the shoulder joint. And they may be missing the target depending on their beam angle to the target tendon. We measured the output by 1000 Hz to be around 2 mW by our standard Thorlab power meter with a sensor size of 1 cm2. In the Yeldan paper they used 2000 Hz for 90 s, which implies that the mean power density was 4 mW/cm2, and dose 0.36 J/cm2. I interpret the dose as too low because WALT recommends minimum 2 Joules per point. It may be interpreted differently as this is partly due to an eventuality with too large spot size which we have not foreseen. From all the basic studies, we know that power densities typically need to be above 5 mW/cm2 before things start to happen, so I will take the initiative to correct guidelines with a minimum power density of 10 mW/cm2 and commenting that this applies for lasers with spot size above 1 cm2.

Liisa Laakso adds her commentary:

I also meant to concur with your observation regarding angle of application of the laser / laser probe to the target tissue. Apart from appropriate dosing, this is one of the biggest flaws in EPA (electrophysical agents) research and clinical application, in my opinion - ie, whether an energy is being applied in an appropriate manner with appropriate technical & methodological issues dealt with so that the energy actually has some chance of reaching the target tissue. For example, the use of ultrasound for the supraspinatus tendon - I'm very doubtful that in studies that have investigated this issue, that the delivery of US energy has been optimised in such studies due to the multitude of issues that can go wrong (including size of transducer, transducer interface, angle of application of transducer, etc.).

The same applies to the way in which a laser probe is angled towards target tissue. With my students, I talk about pumping petrol (the fuel to provide the "energy") in to a car. I use the analogy that no-one goes to a petrol station and pours the fuel over the roof of the car, hoping that the fuel will leak in somewhere and reach the engine to allow the car to be driven. In actuality, we know that if we don't put the nozzle of the petrol pump in to the right place, the fuel won't reach the petrol tank and from there, the engine. In the same way, we must target the application of the EPA device we're using (whether it be laser, US, electrical stimulation etc) to get the best result, in combination with the most accurate dosing parameters (which then raises the analogy of using medications at specific doses and times to gain an effect, but that's another story!).

These are among the many challenges that we face....

WALT2010, Bergen, Norway, September 2010

Our next congress will be held in the city of Bergen, Norway. Chairman of the organizing committee is our new president professor Jan Bjordal. Bergen is the 2nd largest city of Norway, a modern but yet charming city on the Atlantic coast. You can get acquainted with the city already by visiting these sites:

http://www.visitbergen.com/?sp=GB
http://www.tripadvisor.com/Tourism-g190502-Bergen_Hordaland_Western_Fjords-Vacations.html

The editor, only a couple of hundreds of meters away from the congress venue.

Photomedicine and Laser surgery

The quality and popularity of our journal is steadily increasing. Here are some 2008 figures:

A 54% increase in downloads of articles
A 30% increase in submissions
Growth of 16% in the issue content

Congratulations to our hard working editors!

WALT2008 photos

Photos from WALT2008, Sun City, South Africa can be seen on our web site. If you have photos of persons not already featured, please make a contribution, stating the names of all the persons on the photo. We can then expand the gallery. http://www.walt.nu/photo-gallery/index.php

The WALT flyer

On our web site you can find a pdf flyer, introducing WALT and informing about membership. Please print some copies and give it to those you think may be interested in joining.

Research update

You can access the abstracts from our journal Photomedicine and Laser Surgery on our web site. Here are examples of recent research papers from other journals.

Carrasco T G, Mazzetto M O, Mazzetto R G, Mestriner W Jr. Low intensity laser therapy in temporomandibular disorder: a phase II double-blind study. Cranio. 2008; 26 (4): 274-281.

Carrasco selected fourteen patients and divided them into two groups (active and placebo). Infrared laser (780 nm, 70 mw, 60s, 4.2 J/point, 105 J/cm2) was applied precisely and continuously into five points of the temporomandibular joint (TMJ) area: lateral point (LP), superior point (SP), anterior point (AP), posterior point (PP), and posterior-inferior point (PIP) of the condylar position. This was performed twice per week, for a total of eight sessions. A Visual Analogue Scale and a colorimetric capsule method were employed. Data were obtained three times: before treatment (Ev1), shortly after the eighth session (Ev2), and 30 days after the first application (Ev3). Statistical tests revealed significant differences at one percent (1%) likelihood, which implies that superiority of the active group offered considerable TMJ pain improvement. Both groups presented similar masticatory behavior, and no statistical differences were found. With regard to the evaluation session, Ev2 presented the lowest symptoms and highest masticatory efficiency throughout therapy.

da Cunha L A, Firoozmand L M, da Silva A P, Esteves S A, Oliveira W. Efficacy of low-level laser therapy in the treatment of temporomandibular disorder. Int Dent J. 2008; 58 (4): 213-217.

In a study by da Cunha the sample consisted of 40 patients, divided into an experimental group (G1) and a placebo group (G2). The treatment was done with an infrared laser (830nm, 500mW, 20s, 4J/point) at the painful points, once a week for four consecutive weeks. The patients were evaluated before and after the treatment through VAS and the Craniomandibular Index (CMI). The baseline and post therapy values of VAS and CMI were compared by the paired T-test, separately for the placebo and laser groups. A significant difference was observed between initial and final values in both groups. Baseline and post-therapy values of pain and CMI were compared in the therapy groups by the two-sample T-test, yet no significant differences were observed regarding VAS and CMI. After either placebo or laser therapy, pain and temporomandibular symptoms were significantly lower, although there was no significant difference between groups. The actual energy is 500 x 20 seconds = 10 J/point. The two studies above appear to be rather similar, but the study delivering positive results treated twice a week, the negative study once a week. The longer time used in the positive study may also be of importance, even though the energy per point was lower than in the negative study.

França C M, Núñez S C, Prates R A, Noborikawa E, Faria M R, Ribeiro M S. Low-intensity red laser on the prevention and treatment of induced-oral mucositis in hamsters. J Photochem Photobiol B. 2009; 94 (1): 25-31.

França divided a group of hamsters into four groups: preventive cryotherapy, preventive laser, therapeutic laser and therapeutic control group. Mucositis was induced in hamsters by intraperitoneal injection of 5-fluorouracil (5-FU) and superficial scratching. All preventive treatment was performed on the right cheek pouch mucosa. The left pouch mucosa was used for a spontaneous development of mucositis and did not receive any preventive therapy. Laser parameters were: 660 nm, 30 mW, 1.2 J/cm2, 40 s, spot size 3 mm2. Cryotherapy was done positioning ice packs in the hamster mucosa 5 min before 5-FU infusion and 10 min afterwards. To study the healing of mucositis, the left pouch mucosa of each of the hamsters in the TLG received laser irradiation on the injured area. Irradiation parameters were kept the same as above mentioned. The control hamsters in the TCG did not receive any treatment. The mucositis degree and the animal's body mass were evaluated. An assessment of blood vessels was made based on immunohistochemical staining. The CG animals lost 15.16% of their initial body mass while the LG animals lost 8.97% during the first 5 days. The laser treated animals had a better clinical outcome with a faster healing, and more granulation tissue. The quantity of blood vessels at both LG and CG were higher than in healthy mucosa. Regarding the therapeutic analysis, the severity of the mucositis in the TLG was always lower than TCG. TLG presented higher organization of the granulation tissue, parallel collagen fibrils, and increased angiogenesis.

Jaguar G C, Prado J D, Nishimoto I N, Pinheiro M C, de Castro D O Jr, da Cruz Perez D E, Alves F A. Low-energy laser therapy for prevention of oral mucositis in hematopoietic stem cell transplantation. Oral Dis. 2007; 13 (6): 538-543.

In a study by Jaguar 24 patients received prophylactic laser therapy (L+ group). The applications started from the beginning of the conditioning regimen up to day +2. The oral assessment was performed daily until day +30. This group was compared with historical controls, namely 25 patients, who did not receive laser therapy (L- group). All patients developed some grade of mucositis. However, the L- group presented initial mucositis by 4.36 days, whereas the L+ group presented it in 6.12 days. The maximum mucositis occurred between day +2 and day +6 with healing by day +25 in the L- group and between day +2 and day +7 with healing by day +14 for the L+ group. Laser therapy also reduced the time of oral pain from 5.64 to 2.45 days and decreased the consumption of morphine.

Mirzaii-Dizgah I, Ojaghi R, Sadeghipour-Roodsari HR, Karimian SM, Sohanaki H. Attenuation of morphine withdrawal signs by low level laser therapy in rats. Behav Brain Res. 2009; 196 (2): 268-270.

In the study by Mirzaii-Dizgah the effects of LPT on naloxone-induced withdrawal signs of morphine-dependent rats were examined. A GaAlAs laser with a power density of 12.5 J/cm2 was used. One-way ANOVA showed that the LPT applied immediately or 15min prior to naloxone injection significantly decreased total withdrawal score (TWS). These results suggest that LPT prior to naloxone injection attenuates the expression of withdrawal signs in morphine-dependent rats.

Pozza D H, Fregapani P W, Weber J B, de Oliveira M G, de Oliveira M A, Ribeiro Neto N, de Macedo Sobrinho J B. Analgesic action of laser therapy (LLLT) in an animal model. Med Oral Patol Oral Cir Bucal. 2008; 13 (10): 648-652.

The aim of the study by Pozza was to evaluate the analgesic effect of laser therapy on healthy tissue of mice. 45 animals were divided in three groups of 15: A: infrared laser irradiation (830 nm), B: red laser irradiation (660 nm) and C: sham irradiation with laser unit off. After laser application, the mice remained immobilized for the injection of 30 microl of 2% formalin in the plantar pad of the irradiated hind paw. The time that the mouse kept the hind paw lifted was measured at 5 min intervals for 30 minutes. Results showed statistically significant differences comparing the control group with the infrared laser group at 5, 20, 25 and 30 accumulated minutes, and with the red laser group at all time points. The analysis of partial times, at each 5 minutes, showed statistically significant differences between the control and the laser groups up to 20 minutes. Thus, laser irradiation had an analgesic effect and red laser had the best results.

Hagiwara S, Iwasaka H, Hasegawa A, Noguchi T. Pre-Irradiation of blood by gallium aluminum arsenide (830 nm) low-level laser enhances peripheral endogenous opioid analgesia in rats. Anesth Analg. 2008; 107 (3): 1058-1063.

Hagiwara investigated whether pre-irradiation of blood by LPT enhances peripheral endogenous opioid analgesia. The effect of LPT pretreatment of blood on peripheral endogenous opioid analgesia was evaluated in a rat model of inflammation. Additionally, the effect of LPT on opioid production was also investigated in vitro in rat blood cells. The expression of the beta-endorphin precursors, proopiomelanocortin and corticotrophin releasing factor, were investigated by reverse transcription polymerase chain reaction. LPT pretreatment produced an analgesic effect in inflamed peripheral tissue, which was transiently antagonized by naloxone. Correspondingly, beta-endorphin precursor mRNA expression increased with LPT, both in vivo and in vitro. These findings suggest that that LPT pretreatment of blood induces analgesia in rats by enhancing peripheral endogenous opioid production, in addition to previously reported mechanisms.

Shirani A M, Gutknecht N, Taghizadeh M, Mir M. Low-level laser therapy and myofacial pain dysfunction syndrome: a randomized controlled clinical trial. Lasers Med Sci. 2008; Nov 12. [Epub ahead of print]

Myofacial pain dysfunction syndrome (MPDS) is the most common reason for pain and limited function of the masticatory system. The aim of a study by Shirani was to evaluate the efficacy of a particular source producing 660 nm and 890 nm wavelengths that was recommended to reduce of the pain in the masticatory muscles. This was a double-blind and placebo-controlled trial. Sixteen MPDS patients were randomly divided into two groups. For the laser group, two diode laser probes (660 nm, 6.2 J/cm2, 6 min, CW and 890 nm, 1 J/cm2, 10 min, 1,500 Hz were used on the painful muscles. For the control group, the treatment was similar, but the patients were not irradiated. Treatment was given twice a week for 3 weeks. The amount of patient pain was recorded at four time periods (before and immediately after treatment, 1 week after, and on the day of complete pain relief). A visual analog scale was selected as the method of pain measurement.

Chen K H, Hong C Z, Kuo F C, Hsu H C, Hsieh Y L. Electrophysiologic effects of a therapeutic laser on myofascial trigger spots of rabbit skeletal muscles. Am J Phys Med Rehabil. 2008; 87 (12): 1006-1014.

To better understand the mechanisms of therapeutic lasers for treating human myofascial trigger points,Chen designed a blinded controlled study of the effects of a therapeutic laser on the prevalence of endplate noise (EPN) recorded from the myofascial trigger spot (MTrS) of rabbit skeletal muscle. In eight rabbits, one MTrS in each biceps femoris muscle was irradiated with a 660 nm at 9 J/cm2. The contralateral side of muscle was treated with a sham laser. Each rabbit received six treatments. The immediate and cumulative effects were assessed by the prevalence of EPN with electromyographic (EMG) recordings after the first and last treatments. Compared with pretreatment values, the percentages of EPN prevalence in the experimental side after the first and last treatments were significantly reduced. The change in EPN prevalence in the experimental side was significantly greater than in the control side immediately after the first and last treatments. However, no significant differences were noted between the first and last treatments. It seems that laser irradiation may inhibit the irritability of an MTrS in rabbit skeletal muscle. This effect may be a possible mechanism for myofascial pain relief with LPT.

Blaya D S, Guimarães M B, Pozza D H, Weber J B, de Oliveira M G. Histologic study of the effect of laser therapy on bone repair. J Contemp Dent Pract. 2008; 9 (6): 41-48.

This study used histologic analysis and HE staining to evaluate laser biomodulation of bone repair in cavities made in the femurs of rats that underwent non-ablative laser irradiation. METHODS AND MATERIALS: Eighteen male Wistar rats weighing 300 to 400 grams were randomly assigned to three groups of six animals each. A surgical defect site was produced with a trephine about 2 mm in diameter under abundant irrigation. In Group I the complete surgical protocol to produce a bone defect was followed but without laser radiation (control). In Group II a continuous wave 830 nm infrared laser was used at 10 J/cm2 and 50 mW at each point of the surgical site. In Group III a continuous wave 685 nm infrared laser at 10J/cm2 and 35 mW was used at each point of surgical site. The animals were irradiated at intervals of 48 hours beginning immediately after the preparation of the defect and were sacrificed on the 15th, 21st, and 30th days. Slides were studied by means of descriptive analysis. RESULTS: Greater degrees of new bone formation and vertical regeneration were found in the irradiated groups than in the control group. Laser therapy in this study protocol was efficient in promoting bone repair.

Stein E, Koehn J, Sutter W, Wendtlandt G, Wanschitz F, Thurnher D, Baghestanian M, Turhani D. Initial effects of low-level laser therapy on growth and differentiation of human osteoblast-like cells. Wien Klin Wochenschr. 2008; 120 (3-4): 112-117.

The aim of the in vitro study by Stein was to investigate the initial effect of LPT on growth and differentiation of human osteoblast-like cells. SaOS-2 cells were irradiated with laser doses of 1 J/cm2 and 2 J/cm2 using a laser with 670 nm wavelength and an output power of 400 mW. Untreated cells were used as controls. At 24 h, 48 h and 72 h post irradiation, cells were collected and assayed for viability of attached cells and alkaline phosphatase specific activity. In addition, mRNA expression levels of osteopontin and collagen type I were assessed using semi-quantitative RT-PCR. Over the observation period, cell viability, alkaline phosphatase activity and the expression of osteopontin and collagen type I mRNA were slightly enhanced in cells irradiated with 1 J/cm2 compared with untreated control cells. Increasing the laser dose to 2 J/cm2 reduced cell viability during the first 48 h and resulted in persistently lower alkaline phosphatase activity compared with the other two groups. The expression of osteopontin and collagen type I mRNA slightly decreased with time in untreated controls and cells irradiated with 1 J/cm2, but their expression was increased by treatment with 2 J/cm2 after 72 h. These results indicate that LPT has a biostimulatory effect on human osteoblast-like cells during the first 72 h after irradiation.

Ribeiro D A, Matsumoto M A. Low-level laser therapy improves bone repair in rats treated with anti-inflammatory drugs. J Oral Rehabil. 2008; 35 (12) :925-933.

The aim of a study by Ribeiro was to evaluate the action of anti-COX-2 selective drug (celecoxib) on bone repair associated with LPT. A total of 64 rats underwent surgical bone defects in their tibias, being randomly distributed into four groups: Group 1) negative control; Group 2) animals treated with celecoxib; Group 3) animals treated with LPT and Group 4) animals treated with celecoxib and LPT. The animals were killed after 48 h, 7, 14 and 21 days. The tibias were removed for morphological, morphometric and immunohistochemistry analysis for COX-2. Statistical significant differences were observed in the quality of bone repair and quantity of formed bone between groups at 14 days after surgery for Groups 3 and 4. COX-2 immunoreactivity was more intense in bone cells for intermediate periods evaluated in the laser-exposed groups. Taken together, such results suggest that low-level laser therapy is able to improve bone repair in the tibia of rats as a result of an up-regulation for cyclooxygenase-2 expression in bone cells.

Márquez Martínez M E, Pinheiro A L, Ramalho L M. Effect of IR laser photobiomodulation on the repair of bone defects grafted with organic bovine bone. Lasers Med Sci. 2008; 23(3): 313-317.

The study by Márquez Martínez assessed histologically the effect of LPT on the repair of surgical defects on the femur of rats filled with lyophilized bovine bone. The animals were divided into three groups: group I (control); group II (graft); group III (graft + LPT). The animals on the irradiated groups received 16 J/cm2 per session divided into four points around the defect being the first irradiation immediately after surgery and repeated at every 48 h during 2 weeks. Animal death occurred 15, 21, and 30 days after surgery. The specimens were routinely processed and stained with H/E and Sirius red and analyzed by light microscopy. There was histological evidence of improved collagen fiber deposition at early stages of the healing; increased amount of well-organized bone trabeculae at the end of the experimental period on irradiated animals.

Hou J F, Zhang H, Yuan X, Li J, Wei Y J, Hu S S. In vitro effects of low-level laser irradiation for bone marrow mesenchymal stem cells: proliferation, growth factors secretion and myogenic differentiation. Lasers Surg Med. 2008; 40 (10):726-733.

Bone marrow derived mesenchymal stem cells (BMSCs) have shown to be an appealing source for cell therapy and tissue engineering. Previous studies have confirmed that the application of LPT could affect the cellular process. However, little is known about the effects of LPT on BMSCs. The aim of study by Zhang was designed to investigate the influence of LPT at different energy densities on BMSCs proliferation, secretion and myogenic differentiation. BMSCs were harvested from rat fresh bone marrow and exposed to a 635 nm diode laser (60 mW; 0, 0.5, 1.0, 2.0, or 5.0 J/cm2). The lactate dehydrogenase (LDH) release was used to assess the cytotoxicity of LPT at different energy densities. Cell proliferation was evaluated by using 3-(4, 5-dimethylithiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and 5-bromo-2'-deoxyuridine (BrdU) assay. Production of vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) were measured by enzyme-linked immunosorbent assay (ELISA). Myogenic differentiation, induced by 5-azacytidine (5-aza), was assessed by using immunocytochemical staining for the expression of sarcomeric alpha-actin and desmin. Cytotoxicity assay showed no significant difference between the non-irradiated group and irradiated groups. LPT significantly stimulated BMSCs proliferation and 0.5 J/cm2 was found to be an optimal energy density. VEGF and NGF were identified and LPT at 5.0 J/cm2 significantly stimulated the secretion. After 5-aza induction, myogenic differentiation was observed in all groups and LPT at 5.0 J/cm2 dramatically facilitated the differentiation. LPT may provide a novel approach for the preconditioning of BMSCs in vitro prior to transplantation.

Shooshtari S M, Badiee V, Taghizadeh SH, Nematollahi A H, Amanollahi A H, Grami M T. The effects of low level laser in clinical outcome and neurophysiological results of carpal tunnel syndrome. Electromyogr Clin Neurophysiol. 2008; 48 (5): 229-231.

The study by Shooshtari evaluated the effects of LPL through nerve conduction measurement and clinical signs and symptoms. A total of 80 patients were included. Diagnosis of CTS was based on both clinical examination and electromyographic (EMG) findings. Patients were randomly assigned into two groups. Test group (group A) underwent laser therapy (9-11 joules/cm2) over the carpal tunnel area. Control group (group B) received sham laser therapy. Pain, hand grip strength, median proximal sensory and motor latencies, transcarpal median sensory nerve conduction (SNCV) were recorded. After fifteen sessions of irradiation (five times per week), parameters were recorded again and clinical symptoms were measured in both groups. Pain was evaluated by VAS; day-night. Hand grip was measured by Jamar dynometer.There was a significant improvement in clinical symptoms and hand grip in group A. Proximal median sensory latency, distal median motor latency and median sensory latencies were significantly decreased. Transcarpal median SNCV increased significantly after laser irradiation. There were no significant changes in group B except changes in clinical symptoms.

Zhang L, Xing D, Zhu D, Chen Q. Low-power laser irradiation inhibiting Abeta25-35-induced PC12 cell apoptosis via PKC activation. Cell Physiol Biochem. 2008; 22 (1-4): 215-222.

Apoptosis is a contributing pathophysiological mechanism of Alzheimer's disease (AD). In a study by Zhang the techniques of fluorescence resonance energy transfer (FRET) and real-time quantitative RT-PCR were used to investigate the anti-apoptotic mechanism of LPT. Rat pheochromocytoma (PC12) cells were treated with amyloid beta 25-35 (Abeta(25-35)) for induction of apoptosis before LPT treatment. The cell viability assays and morphological examinations show that low fluence of LPT (0.156 J/cm2-0.624 J/cm2) could inhibit the cells apoptosis. An increase of PKC activation was dynamically monitored in the cells treated with PMA (specific activator of PKC), LPT only or Abeta(25-35) followed by 5 min LPT treatment, respectively. However, the effect of LPT activating PKC could be inhibited by Go 6983 (specific inhibitor of PKC). Furthermore, LPT involved an increase in mRNA of the cell survival member bcl-xl and a decrease in the up-regulation of cell death member bax mRNA caused by Abeta(25-35). Further data show that low fluence of LPT could reverse the increased level of bax/bcl-xl mRNA ratio caused by Abeta(25-35) treatment. In addition, Go 6983 could inhibit the decreased level of bax/bcl-xl mRNA ratio. Taken together, these data clearly indicate that LPT inhibited Abeta(25-35)-induced PC12 cell apoptosis via PKC-mediated regulation of bax/bcl-xl mRNA ratio.

Gál P, Mokrý M, Vidinský B, Kilík R, Depta F, Harakaľová M, Longauer F, Mozeš S, Sabo J. Effect of equal daily doses achieved by different power densities of low-level laser therapy at 635 nm on open skin wound healing in normal and corticosteroid-treated rats. Lasers Med Sci. 2008 Aug 21. [Epub ahead of print]

In a study by Gál, four round, full-thickness skin wounds were made on the backs of 48 rats that were divided into two groups (non-steroid laser-treated and steroid laser-treated). Three wounds were stimulated daily with a diode laser (daily dose 5 J/cm2), each with different power density (1 mW/cm2, 5 mW/cm2, and 15 mW/cm2), whereas the fourth wound served as a control. Two days, 6 days, and 14 days after surgery, eight animals from each group were killed and samples were removed for histological evaluation. In the non-steroid laser-treated rats, significant acceleration of epithelization and collagen synthesis 2 days and 6 days after surgery was observed in laser-stimulated wounds. In steroid laser-treated rats, 2 days and 14 days after surgery, a decreased leucocyte/macrophage ratio and a reduction in the area of granulation tissue were recorded, respectively. LPT improved wound healing in the non-steroid laser-treated rats, but it was not effective after corticosteroid treatment.

Yasukawa A, Hrui H, Koyama Y, Nagai M, Takakuda K. The effect of low reactive-level laser therapy (LLLT) with helium-neon laser on operative wound healing in a rat model. J Vet Med Sci. 2007; 69 (8): 799-806.

The effect of low reactive-level laser therapy (LLLT) with a He-Ne laser on operative wound healing was investigated in a rat model. 10-millimeter surgical wounds were created on the backs of Sprague Dawley rats, and animals were assigned to one of eleven groups (n=5). Ten groups received either 8.5 mW or 17.0 mW irradiation of 15 seconds LLLT a day with one of five different irradiation frequencies, i.e. daily (from the 1st to 6th day following surgery), every other day (the 1st, 3rd, and 5th day), on only the 1st day, on only the 3rd day, and on only the 5th day; the 1st day was the day following the surgery. The control group received no irradiation. A skin specimen was harvested from the dorsal thoracic region on the 7th day to measure the rupture strength. The control group had the lowest rupture strength (5.01 N), and the 17.0 mW every other day irradiation group had the highest rupture strength (13.01 N). Statistical differences were demonstrated in the 8.5 mW irradiation setting between the every other day irradiation group and the control group (p<0.05); and in 17.0 mW irradiation setting between the everyday irradiation, the every other day, and the 1st day only groups vs. the control group (p<0.01). Histological examination demonstrated that wound healing in the 17.0 mW every other day irradiation group was promoted most significantly such as the prevention of excessive inflammation, increased formation of collagen fibers, and recovery in continuity of tissues. The control group showed poor wound healing and the other experimental groups showed intermediate healing. Thus LLLT with a He-Ne laser was found to promote the healing of operative wounds in the present rat model, in which the most favorable application of LLLT was the 17.0 mW setting of 15 seconds a day with a frequency of every other day.

Lapchak P A, Han M K, Salgado K F, Streeter J, Zivin J A. Safety profile of transcranial near-infrared laser therapy administered in combination with thrombolytic therapy to embolized rabbits. Stroke. 2008; 39 (11): 3073-3078.

Transcranial near-infrared laser therapy (TLT) is currently under investigation in a pivotal clinical trial that excludes thrombolytic therapy. To determine if combining tissue plasminogen activator (tPA; Alteplase) and TLT is safe, this study assessed the safety profile of TLT administered alone and in combination with Alteplase. The purpose for a study by Lapchak was to determine if the combination of TLT and thrombolysis should be investigated further in a human clinical trial. The researchers determined whether postembolization treatment with TLT in the absence or presence of tPA would affect measures of hemorrhage or survival after large clot embolism-induced strokes in rabbits. TLT did not significantly alter hemorrhage incidence after embolization, but there was a trend for a modest reduction of hemorrhage volume (by 65%) in the TLT-treated group compared with controls. Intravenous administration of tPA, using an optimized dosing regimen, significantly increased hemorrhage incidence by 160%. The tPA-induced increase in hemorrhage incidence was not significantly affected by TLT, although there was a 30% decrease in hemorrhage incidence in combination-treated rabbits. There was no effect of TLT on hemorrhage volume measured in tPA-treated rabbits and no effect of any treatment on 24-hour survival rate. In the embolism model, TLT administration did not affect the tPA-induced increase in hemorrhage incidence. TLT may be administered safely either alone or in combination with tPA because neither treatment affected hemorrhage incidence or volume. These results support the study of TLT in combination with Alteplase in patients with stroke.

Dos Reis F A, Belchior A C, de Carvalho P D, da Silva B A, Pereira D M, Silva I S, Nicolau R A. Effect of laser therapy (660 nm) on recovery of the sciatic nerve in rats after injury through neurotmesis followed by epineural anastomosis. Lasers Med Sci. 2008 Dec 23. [Epub ahead of print]

The aim of a study by dos Reis was to analyze the influence of 660 nm laser light on the myelin sheath and functional recovery of the sciatic nerve in rats. The sciatic nerves of 12 Wistar rats were subjected to injury through neurotmesis and epineural anastomosis, and the animals were divided into two groups: group 1 was the control and group 2, underwent LPT. After the injury, 660 nm, 4 J/cm2, 26.3 mW and beam area of 0.63 cm2 was administered to three equidistant points on the injury for 20 consecutive days. In the control group the mean area of the myelin impairment was 0.51 on day 21 after the operation, whereas this value was 1.31 in the LPT group. Comparison of the sciatic functional index (SFI) showed that there was no significant difference between the pre-lesion value in the laser therapy group and the control group. The use of 660 nm LPT provided significant changes to the morphometrically assessed area of the myelin sheath, but it did not culminate in positive results for functional recovery in the sciatic nerve of the rats after injury through neurotmesis.

Igić M, Kesić L, Apostolović M, Kostadinović L. [Low-level laser efficiency in the therapy of chronic gingivitis in children] [in Serbian]. Vojnosanit Pregl. 2008; 65 (10): 755-757.

The aim of a study by Igić was to determine the efficiency of a LPT in the therapy of chronic gingivitis in children. The study included 100 children with permanent dentition and suffering from chronic gingivitis. They were divided into two groups: group I-50 children with chronic gingivitis, who underwent the basic therapy; group II-50 children with chronic gingivitis, who underwent the basic therapy and also LPT. Evaluation of the condition of oral hygiene, the health of gingiva and periodontium was done using appropriate index before and after the therapy. For the plaque index (PI) following results were obtained: in the group I PI = 1.94, and in the group II PI = 1.82. After the therapy in both groups PI was 0. In the group I sulcus plaque index (SPI) was 2.02 before the therapy and 0.32 after the therapy. In the group II SPI was 1.90 before the therapy and 0.08 after the therapy. In the group I Community Periodontal Index of Treatment Needs (CPITN) was 1.66 before the therapy and 0.32 after the therapy, and in the group II CPITN was 1.60 before the therapy and 0.08 after the therapy. Chronic gingivitis in children can be successfully cured by the basic treatment but the use of LPT can significantly improve this effect.

Aimbire F, de Lima F M, Costa M S, Albertini R, Correa J C, Iversen V V, Bjordal J M. Effect of low level laser therapy on bronchial hyper-responsiveness. Lasers Med Sci. 2008 Nov 12. [Epub ahead of print]

The objective of a study by Aimbire was to investigate whether LPT could reduce bronchial hyper-responsiveness (BHR) induced by tumour necrosis factor-alpha (TNF-alpha) modulating the metabolism of inositol phosphate (IP) in bronchial smooth muscle cells (BSMCs). The study was on 28 Wistar rats, randomly divided into four groups. Irradiation (1.3 J/cm2) was administered 5 min and 4 h after bronchial smooth muscle (BSM) had been suspended in TNF-alpha baths, and the contractile response-induced calcium ion (Ca2+) sensitization was measured. The BSMCs were isolated, and the IP accumulation was measured before and after TNF-alpha immersion in the groups that had been irradiated or not irradiated. BSM segments significantly increased contraction 24 h after TNF-alpha immersion when exposed to carbachol (CCh) as Ca2+, but it was significantly reduced by 64% and 30%, respectively, after laser treatment. The increase in IP accumulation induced by CCh after TNF-alpha immersion was reduced in the BSMCs by LPT. The dose of 2.6 J/cm2 reduced BHR and IP accumulation in the rats' inflammatory BSMCs.

Wu C S, Hu S C, Lan C C, Chen G S, Chuo W H, Yu H S. Low-energy helium-neon laser therapy induces repigmentation and improves the abnormalities of cutaneous microcirculation in segmental-type vitiligo lesions. Kaohsiung J Med Sci. 2008; 24 (4): 180-189.

Since segmental-type vitiligo lesions (SV) are resistant to conventional forms of therapy, its management represents a challenge for dermatologists. HeNe laser, wavelength 632.8 nm has been employed as a therapeutic instrument in many clinical situations, including vitiligo management and repair of nerve injury. The purpose of the study by Wu was to evaluate the effectiveness and safety of HeNe lasers in treating SV, and determine the effects on the repair of sympathetic nerve dysfunction. Forty patients with stable-stage SV on the head and/or neck were enrolled in this study. He-Ne laser irradiation was administered locally at 3.0 J/cm2 with point stimulation once or twice weekly. Cutaneous microcirculatory assessments in six SV patients were performed using a laser Doppler flowmeter. The sympathetic adrenoceptor response of cutaneous microcirculation was determined by measuring cutaneous blood flow before, during and after iontophoresis with sympathomimetic drugs (phenylephrine, clonidine and propranolol). All measurements of microcirculation obtained at SV lesions were simultaneously compared with contralateral normal skin, both before and after HeNe laser treatment. After an average of 17 treatment sessions, initial repigmentation was noticed in the majority of patients. Marked repigmentation was observed in 60% of patients with successive treatments. Cutaneous blood flow was significantly higher at SV lesions compared with contralateral skin, but this was normalized after HeNe laser treatment. In addition, the abnormal decrease in cutaneous blood flow in response to clonidine was improved by HeNe laser therapy.

Acupunct Electrother Res. 2007; 32(1-2): 818-6. Depth of penetration of an 850nm wavelength low level laser in human skin. Esnouf A, Wright PA, Moore JC, Ahmed S.

Low Level Laser Therapy is used for a wide variety of conditions including superficial skin sores, musculoskeletal and joint problems, and dentistry. Knowledge of the penetration depth of laser radiation in human skin is an essential prerequisite to identifying its method of action. Mathematical simulations and estimates from the literature suggest that the depth of penetration of laser radiation using wavelengths from 630nm up to 1100nm may be up to 50mm. The aim of this study is to directly measure the penetration depth of a Low Level Laser in human tissue. Human abdominal skin samples up to 0.784mm thickness were harvested by dermatome following abdominoplasty procedures. These samples were irradiated by a Gallium Aluminium Arsenide Laser (Wavelength 850nm near infra-red invisible light, 100mW, 24kHz, 0.28mm diameter probe) and the transmitted radiation measured with an Ophir Optronics 'Nova' external energy meter. The intensity of laser radiation reduced by 66% after being transmitted through a 0.784mm sample of human abdominal tissue. In this study most laser radiation was absorbed within the first 1mm of skin.

Gottschling S, Meyer S, Gribova I, Distler L, Berrang J, Gortner L, Graf N, Shamdeen M G. Laser acupuncture in children with headache: a double-blind, randomized, bicenter, placebo-controlled trial. Pain. 2008; 137 (2): 405-412.

The aim of the studdt by Gottschling was to investigate whether laser acupuncture is efficacious in children with headache and if active laser treatment is superior to placebo laser treatment, in a prospective, randomized, double-blind, placebo-controlled trial of low level laser acupuncture in 43 children with headache, either migraine (22 patients) or tension type headache (21 patients)). Patients were randomized to receive a course of 4 treatments over 4 weeks with either active or placebo laser. The treatment was highly individualised based on criteria of Traditional Chinese medicine (TCM). The primary outcome measure was a difference in numbers of headache days between baseline and the 4 months after randomization. Secondary outcome measures included a change in headache severity using a 10 cm Visual Analogue Scale for pain and a change in monthly hours with headache. Measurements were taken during 4 weeks before randomization (baseline), at weeks 1-4, 5-8, 9-12 and 13-16 from baseline. The mean number of headaches per month decreased significantly by 6.4 days in the treated group) and by 1.0 days in the placebo group. Secondary outcome measures headache severity and monthly hours with headache decreased as well significantly at all time points compared to baseline and were as well significantly lower than those of the placebo gro The aim of a study By Ahmed was to investigate the effects of three different intensities of infrared diode laser radiation on amino acid neurotransmitters in the cortex and hippocampus of rat brain. Lasers are known to induce different neurological effects such as pain relief, anesthesia, and neurosuppressive effects; however, the precise mechanisms of these effects are not clearly elucidated. Amino acid neurotransmitters (glutamate, aspartate, glutamine, gamma-aminobutyric acid [GABA], glycine, and taurine) play vital roles in the central nervous system (CNS). The shaved scalp of each rat was exposed to different intensities of infrared laser energy (500, 190, and 90 mW) and then the rats were sacrificed after 1 h, 7 d, and 14 d of daily laser irradiation. The control groups were exposed to the same conditions but without exposure to laser. The concentrations of amino acid neurotransmitters were measured by high-performance liquid chromatography (HPLC). The rats subjected to 500 mW of laser irradiation had a significant decrease in glutamate, aspartate, and taurine in the cortex, and a significant decrease in hippocampal GABA. In the cortices of rats exposed to 190 mW of laser irradiation, increases in aspartate accompanied by a decrease in glutamine were observed. In the hippocampus, other changes were seen. The rats irradiated with 90 mW showed a decrease in cortical glutamate, aspartate, and glutamine, and an increase in glycine, while in the hippocampus an increase in glutamate, aspartate, and GABA were recorded. It is concluded that daily laser irradiation at 90 mW produced the most pronounced inhibitory effect in the cortex after 7 d. This finding may explain the reported neurosuppressive effect of infrared laser energy on axonal conduction of hippocampal and cortical tissues of rat brain.

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In the next issue you can read a summary of the interesting work of the Laser Research Group at the University of Johannesburg. And please feel free to make a contribution. It could be a report from a congress, ideas about new development in lasers, analyses of published research, case reports etc. We reserve the right to edit or deny publication but the policy will be generous.