The Physics of 'Mr. Ed' in the Big Apple

At Tufts, investigators are on the cutting edge of pulmonary disease research. From their results, fundamental knowledge and advances are made contributing to the health and welfare of animals and humans. In addition, this pulmonary research can help determine the impact that environmental conditions have on breathing biological systems and thus serve to a better understanding of many of the environmental issues facing us today. With one of these techniques, called forced oscillation mechanics or FOM, the air mass comprising the pulmonary system of a horse, the nose, throat and lungs, is set into slight oscillations by inaudible sound waves of defined frequencies via a mask that the horse must wear (this does not bother the horse at all and the horse usually gets a good head scratching while this goes on). The measurable characteristics of the oscillations set up in the mask and the horse’s airway as determined by the flow, amplitude and phase with respect to the original sound wave, have direct correspondence to parameters related to biology and health and well being of the horse's pulmonary system. To a physicist, this is the most interesting accoustic-Helmholtz oscillator ever fashioned. In fact, the 'jargon' for the pulmonary parameters related to the horse are borrowed from electrical circuits in physics such as R (resistance), L (inductance) and C (capacitance) because the same equations, phenomena and interpretations governing the Helmholtz oscillator also describe the behavior of AC-electrical circuits. In a second technique called inductance plethysmography (better known as the flowmetric system), a flexible band stretches around the horse's abdomen. Sewn in the band is a sinusoidal pattern of wire. When the horse breathes, inhaling or exhaling, the stretch of the fabric causes the wound-wire pattern to expand or contract. If the wire carries a small electrical current, changes in the physical pattern of the wire cause changes in 'magnetic flux lines' from the current in the wire. This effect, Lenz's Law or inductance, produces a measurable voltage directly proportional to the breathing properties of the horse. Measured in conjunction with the inhaled and expired flow of air from the horse, parameters related to biology and health of the subject's pulmonary system can be determined.

If Mr. Ed the horse sounds like he's got a lot of physics in him, the Tufts researchers surely agree and they were therefore kind enough to see the potential for my involvement and contributions. The most beautiful of these researchers, and she happens to be my wife, is Dr. Melissa Mazan. She is the Director of Sports Medicine at Tufts. She and her colleagues very successfully use these techniques, and others, to win major grants from national sources and advance the knowledge of diseases in animals and humans. I had hoped to be able to contribute to the experiment design, data acquisition development and actual testing and perhaps most significantly with the theoretical modeling.

With my own pulmonary 'issues' including asthma and severe allergies to horses…. Yes horse aside, I had great personal success setting the seed for future collaborations that soon I am hopeful will include BSC students. A different technique, known as open respirometry, has been used for many years at TUSVM to measure the amount of oxygen a horse consumes, and the amount of carbon dioxide a horse produces during a treadmill exercise - where the horse is running at racing speed, and consuming upwards of 2000 liters of air per minute. It seemed that this same system should work for measuring energy consumption at rest - but the now the changes that the researchers were trying to measure were very small, and the error was unacceptably high. In order to solve this problem, I helped develop what is called a mixing chamber. In general, the air-analysis system used for this procedure takes differential or instantaneous measurements of the gas levels from horses. A mixing chamber, simply a large chamber from which the gases can be stored and mixed appropriately and for a period just right to average and not wash out significant data was suggested by a post-doc. I helped come up with the working design of the flow mixer that does involve a large trashcan in true physics style. The entire system now works fabulously.

I also recently collaborated on one of the inductance plethysmography experiments designed by my wife using ten horses. This was no ordinary bunch of horses or laboratory. In fact, the experiments were done in Manhattan New York on the corner of 89^th and Amsterdam where the horse live. Because of the sheer size and volume flow of air needed by horses to breath and exercise, the plan of the experiment was to see if horse pulmonary disease might be sentinel to human problems related to environmental and atmospheric conditions. Thus it was planned to test and compare the pulmonary parameters of horses living in rural (New Hampshire) and city (New York) settings using in conjunction EPA data of the levels and kinds of pollutants and particulate matter in the different regions. As the sad history-making events unfolded that unforgettable Tuesday, the original date for testing the NY horses, Sept. 17 had to be canceled. The measurements took new meaning however. Questions following the collapse of the World Trade Center included health effects caused by air born particles. Could our measurements give some insight? Our experiments eventually took place on what could only be described as a spectacular clear and beautiful day on September 26. On that day, we measured the pulmonary functions of ten horses whose jobs are to cater to the people of Central Park and who live at their very own horse-apartment building on 89^th across from Central Park called Claremont Riding Stables. The stable has been there for over one hundred years and the horses literally walk from their bedrooms, ok stables, on the upper floors down ramps (no stairs here) to the riding arena. There are 50 residents in all in the apartment on 89^th including some celebrities that have appeared on Broadway, television and movies. One movie in particular, apparently, in which the actor William Hurt was seen in a chase scene up and down the ramps of Claremont. The experiments went extremely well and we have just now begun analyzing the data. Preliminary results indicate differences between the city and rural horses as suspected; however, no clear indication has been seen thus far pointing to specific effects of the air born pollutants from the Sept. 11 events.

I obviously hope to continue this collaboration and expand it in several ways. The Tufts team is enthusiastic about potential contributions that I can make by creating a laboratory at BSC where mechanical models of the pulmonary system can be built in conjunction with the Tufts research. These would be biology-specific mechanical and electrical Helmholtz oscillator experiments which also require that sophisticated theoretical and computer simulation programs be developed in parallel. Both the experimental and theoretical works are ideally suited for my students and me at Bridgewater State College. This type of laboratory and research offers the Tufts researchers a sort of experimental and theoretical 'control' case with respect to the more complex living subject that they see. The ability to specify and vary individually the variables of the control system will help to isolate and better understand specific features of the data taken from the more intricate living systems. My students and I may be able to resolve data and questions that Tufts researchers cannot isolate, we may suggest new methods and techniques for measurements along with writing new code for the data acquisition, we can suggest and design new experiments all together and expand and create new theoretical models. Our work could add up to more precise, or perhaps even entirely new, connections between experiment and model, disease and biology and even environment and disease. I have been asked to continue with these collaborations and to include BSC students on the Tufts research at Tufts University itself or in the field (sometimes literally). In addition, my students and I will be a part of a truly cross-disciplinary research program drawing in students from BSC with physics, chemistry, environmental and biology interests. I hope to win funding from CART once again this fall to begin to purchase the equipment to make this lab a reality here at BSC.