An experimental treatment rejuvenates (使...恢复活力) the immune (免疫的) systems of older mice, improving their ability to fight infections. If it works in humans, the treatment could reverse (逆转) age-related decreases in immunity that leave older adults susceptible to disease.

These decreases may be due to changes in our blood stem cells which can develop into any type of blood cell—including key parts that make up the immune system. As we age, a larger proportion (比例) of these stem cells tend to produce some immune cells over others, says Jason Ross at Stanford University in California. This imbalance damages the immune system’s defenses.

Ross and his colleagues have developed a treatment using antibodies (抗体), which are proteins that recognize and attack certain cells to target these abnormal stem cells. They tested the treatment in six mice between 18 and 24 months old, which is roughly equal to an age of 56 to 70 years in humans.

A week after receiving an antibody injection, the mice had about 38 percent fewer of these abnormal stem cells than six mice of the same age that didn’t receive the treatment. “You can think of it as kind of turning back the clock,” says Ross. “We’re making the proportion of these immune cells more similar to those of a younger adult mouse.”

To test if the changes resulted in a stronger immune system, the researchers vaccinated (打疫苗) 17 older mice against a mouse virus. Nine of these mice had received the antibody treatment eight weeks earlier. The researchers then infected (感染) the mice with the virus. Two weeks later, they measured the number of infected cells in the animals and found that nearly half of the treated mice had cleared the infection, compared with only one of the eight untreated mice.

The findings indicate that the antibody treatment rejuvenates the mouse immune system. “Since humans, like mice, also see abnormal blood stem cells increase with age, a similar antibody treatment may rejuvenate our immune systems,” says Ross.

Neudy Rojop, 29, looks across the rough, rocky road in the small rural village of San Rafael Pacaya. It leads to the home where she grew up and where she still lives today.

When Rojop was about 10, her cousin, Carlos, was very sick. Without any local clinics (诊所), Rojop’s family couldn’t even figure out what the disease was. They could do nothing but wait. Growing up, she noticed how frequently many of those around her were getting sick. As a teenager, she started to realize her community needed better chance to health care. So she determined to go to a nursing school.

But her vision was beyond being a nurse. After graduation, she realized one person was not enough to make the community better. “The people here may have common diseases,” she thought. “Some are known. But there may be new diseases that we don’t know about.” She wanted to do something to keep any illness from being a threat in the first place. She wanted to train people and do some research to monitor these illnesses and try to provide early actions, or try out new ways to prevent some of them.

Over the next few years, she and a small team brought her vision to life. They provided measures that could limit the possible risks. Olson, one of her colleagues, recalled, “She has zero clinical experience and zero research experience at first, but now she is a superstar here. Her working place is usually busy with about 300 patients per month.”

Now Rojop starts her days with a morning meeting, making decisions, solving problems and setting priorities with her teammates. “In the past, I was so young that I could do nothing for my community,” she says. “But now I can help because I know how.”

What would happen today, if there was an accident at your workplace? Would employees know what to do? Would the injured person get the best possible care?

When an accident happens, a first-aid programme that meets the requirements of the law and is made to the type and size of the workplace can really make a difference between life and death, or between recovery and lasting disablement (伤残).

Employers should make sure that all employees know where emergency information is posted at the workplace. The emergency notice should show the phone numbers of the closest ambulance service, rescue unit, fire police station, and hospital. The amount of time it takes to look up one of these important numbers can make a big difference to a seriously injured person. The place of first-aid equipment and rescue equipment should also be posted.

All workplaces should have a person with first-aid or medical training in case of an emergency. First-aid equipment and supplies, including a variety of dressings and instruments, as well as an up-to-date first-aid book, should be stored where they can be reached quickly and easily in case of an accident. These supplies should be inspected frequently, making sure they are kept in sanitary (卫生的) and usable conditions and re-stored after use. Larger workplaces may need more than one fully-equipped first-aid bag.

In lonely workplaces, emergency supplies and an action plan are especially important. At least one person trained in first aid should always be on-site (在现场的). If first aid is not given properly, it can sometimes hurt rather than help an injured person, or even be harmful to the person giving first aid.

All workers should know who is trained to give first aid on-site, where first-aid equipment is put, and what medical professionals or medical instruments should be found if a medical emergency happens.