Needle-Free Injections

January 1, 2005 by Natalie Salat

It may seem like something out of Star Trek, but doctors at the Harvard-MIT Division of Health Sciences and Technology are well on their way to developing painless, needle-free injections. Instead of relying on the standard hypodermic needle to deliver medication or extract body fluids, Dr. James Weaver and his fellow researchers have developed a technique using a strong jet of air laced with tiny, sharp aluminum oxide crystals to penetrate the skin. In the procedure, called microscission, a steady stream of gas pelts the crystals through the skin’s top layers to create a microscopic hole that is up to one-fifth of a millimetre deep.

This hole, through which drug molecules can be delivered or a small sample of blood extracted, is only about a quarter of a millimetre in diameter, or a few times the diameter of a human hair. In the study, which used several adult volunteers, Weaver and fellow scientists were able to obtain the 1.5 cubic centimetres of blood needed for blood glucose testing, and also effectively administered the local anesthetic lidocaine by applying a cotton swab to the minuscule hole, or microconduit.

The procedure takes less than 20 seconds and is virtually pain-free. “You feel a gentle stream of air and then a faint tingling sensation, which is not from the microscission but from the blood reacting with the tissue as it trickles to the surface,” explained Weaver. After a couple of hours, there’s a small red ring around the hole, but that disappears quickly, he added. “Although the hole is small on a human scale, it’s absolutely huge on a molecular scale.”

Although further investigation is needed into what happens once drug molecules are inside the skin, Weaver noted that the basic idea of microscission works. “In the future, we are highly optimistic that we’ll be able to do it faster, with equipment that is relatively inexpensive and easy to use.”

For The Public Good

Canada has a new public health agency and national public health officer to oversee the government’s efforts to keep Canadians well. The Public Health Agency of Canada, headed by Dr. David Butler-Jones, will have offices across the country and is to focus on emergency preparedness and response, infectious and chronic disease prevention and control, injury prevention and health promotion.

In the wake of the severe acute respiratory syndrome (SARS) debacle of 2003, the government has poured more than $600 million into increasing Canada’s front-line public health capacity and adding new vaccine programs, and another $165 million to help create the agency and address gaps in the public health system.

Butler-Jones, who is based in Winnipeg, takes on the leadership of the public health agency with a vast and varied medical background. Besides having served as Saskatchewan’s medical officer of health from 1995 to 2002 and more recently as a member of the National Advisory Committee on SARS and Public Health, he is an active member of organizations such as the Canadian Public Health Association and continues to teach and conduct clinical research.

“Canada’s chief public health officer must demonstrate clear leadership, not only in times of emergency, but also in helping Canadians stay healthy and out of the hospital,” said Prime Minister Paul Martin in September. “Dr. Butler-Jones has the qualities and expertise to launch our public health agency and to make it a success.”

The new public health officer said he would work closely with the minister of Health and the medical officers of health from every province and territory to “design an effective, coordinated public health system that serves our citizens.” Part of his mandate is to inform and engage Canadians about health issues.

Even still, there are other options for Canadians to get timely information—the Internet, and your doctor. Not sure where to start looking? In this computer age, your physician may be able to provide you with a quick, free ‘information prescription’. In the meantime, some reputable sites include that of the Canadian Medical Association, www.cma. ca, the Canadian Women’s Health Network, www.cwhn.ca, the Mayo Clinic, www.mayohealth.org and Health Canada, www.hc-sc.gc.ca.

Preventing Modern-Day Strains

With more and more people glued to their computers—surfing the Internet, playing video games, doing their finances—there has been a corresponding increase in the aches and pains associated with long stints in front of a computer. Neck, shoulders, back, wrist and elbow joints take a beating due to poor posture, office setup and work habits. Good posture is especially important, as slouching at the keyboard puts increased strain on the spine and limbs.

The Canadian Physiotherapy Association offers a number of preventative tips on its Web site, www.physiotherapy. ca. For a start, stretch regularly and make sure to get up off your seat once in a while to promote blood flow and change your body position. Sitting for extended periods in one position doesn’t do the body good. Also, vary your tasks to prevent repetitive strain.

As for your workstation, make sure your eyes are level within the top third of the screen, and that your keyboard and mouse are centred in front of the monitor and close to you, so you don’t have to contort your body to use them. Sit with your buttocks right back in the chair, feet flat on the floor or on a foot rest, and knees bent at a 90-degree angle. Ergonomic computer accessories such as a wrist pad on the keyboard will allow you to rest your wrists and reduce strain.

Finally, make sure you exercise your body as well as your mind. The CPA recommends at least 30 minutes of stretching and physical activity every day.

Irresistible Cravings

If you think the mere sight of food makes you pack on the pounds, you may not be miles off the mark. A team of United States researchers have found that exposure to food—through sight and smell, without actually eating—increases brain metabolism and correlates with self-reports of hunger and desire for food. The team of Dr. Gene-Jack Wang of the Brookhaven National Laboratory in New York State also found that the same area of the brain that is involved in drug addiction, drive and pleasure—the right orbitofrontal cortex—is also affected by the desire for food.

“These results could explain the deleterious effects of constant exposure to food stimuli, such as advertising, candy machines, food channels and food displays in stores,” said Wang, the study’s lead author. “The high sensitivity of this brain region to food stimuli, coupled with the huge number and variety of these stimuli in the environment, likely contributes to the epidemic of obesity in this country.” He suggested that, when our brains are constantly in craving mode, it becomes very difficult to resist eating more than we need.

In the study, published last year in NeuroImage, the researchers used brain scanning to investigate how 12 hungry adults of normal weight responded to their favourite foods. The volunteers were asked not to eat anything 17 to 19 hours before undergoing positron emission tomography scans. Before the tests, they received an injection containing a radiotracer, a radioactive chemical tag that would highlight activated areas of the brain. They underwent two scans a day, one when they were exposed to their favourite foods and the other without food stimulation. Participants also had to describe, on a scale of one to 10, whether they felt hungry or desired food at the start of the study and at five-minute intervals for a total of 45 minutes.

Wang and company found that food stimulation dramatically raised brain activity and resulted in increased hunger and desire for food. The increased reports of hunger correlated with a higher metabolism in the right orbitofrontal cortex, which controls the senses of pleasure and reward.

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