Organ donation takes healthy organs and tissues from one person for transplantation into another. Experts say that the organs from one donor can save or help as many as 50 people. Organs you can donate include:

• Internal organs: Kidneys, heart, liver, pancreas, intestines, lungs
• Skin
• Bone and bone marrow
• Cornea

Most organ and tissue donations occur after the donor has died. But some organs and tissues can be donated while the donor is alive.

People of all ages and background can be organ donors. If you are under age 18, your parent or guardian must give you permission to become a donor. If you are 18 or older you can show you want to be a donor by signing a donor card. You should also let your family know your wishes.

Health Resources and Services Administration

Osteonecrosis is a disease caused by reduced blood flow to bones in the joints. In people with healthy bones, new bone is always replacing old bone. In osteonecrosis, the lack of blood causes the bone to break down faster than the body can make enough new bone. The bone starts to die and may break down.

You can have osteonecrosis in one or several bones. It is most common in the upper leg. Other common sites are your upper arm and your knees, shoulders and ankles. The disease can affect men and women of any age, but it usually strikes in your thirties, forties or fifties.

At first, you might not have any symptoms. As the disease gets worse, you will probably have joint pain that becomes more severe. You may not be able to bend or move the affected joint very well.

No one is sure what causes the disease. Risk factors include :

• Long-term steroid treatment
• Alcohol misuse
• Joint injuries
• Having certain diseases, including arthritis and cancer

Doctors use imaging tests and other tests to diagnose osteonecrosis. Treatments include medicines, using crutches, limiting activities that put weight on the affected joints, electrical stimulation and surgery.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Osteoporosis is a disease in which your bones become weak and are likely to fracture (break). The disease can develop when your bone mineral density and bone mass decrease. It can also happen if the structure and strength of your bones change.

Osteoporosis is called a "silent" disease because it doesn't usually cause symptoms. You may not even know you have the disease until you break a bone. This could happen with any bone, but it's most common in the bones of your hip, vertebrae in the spine, and wrist.

Your bones are made of living tissue. To keep them strong, your body breaks down old bone and replaces it with new bone. Osteoporosis develops when more bone is broken down than replaced. You lose bone mass and changes happen in the structure of your bone tissue. This can happen as you get older. Other risk factors can also lead to the development of osteoporosis or increase your chance of developing the disease.

Anyone can develop osteoporosis, but you are more likely to develop it if you have one or more risk factors:

• Your sex. Osteoporosis is more common in women, especially after menopause (postmenopausal).
• Your age. Your risk increases as you get older. It is most common in people over age 50.
• Your body size. It is more common in people who are slim and thin boned.
• Your race:
  • White and Asian women are at highest risk.
  • African American and Mexican American women have a lower risk.
  • White men are at higher risk than African American and Mexican American men.
• Family history. Your risk of osteoporosis may be higher if one of your parents has osteoporosis or broke their hip.
• Changes to hormones. Low levels of certain hormones can increase your chance of developing osteoporosis.
• Diet. A diet that is low in calcium and/or vitamin D or does not include enough protein can raise your risk.
• Long-term use of certain medicines, such as:
  • Corticosteroids
  • Proton pump inhibitors (which treat GERD)
  • Medicines to treat epilepsy
• Having other medical conditions, such as:
  • Endocrine diseases
  • Certain digestive diseases
  • Rheumatoid arthritis
  • Certain types of cancer
  • HIV
  • Anorexia nervosa, a type of eating disorder
• Your lifestyle. Certain lifestyle factors can contribute to bone loss, such as:
  • Smoking tobacco
  • Long-term heavy alcohol use
  • Physical inactivity or prolonged periods of bedrest

Osteoporosis usually doesn't cause symptoms. You may not know that you have it until you break a bone.

Health care providers often diagnose osteoporosis during routine screening for the disease. The U.S. Preventive Services Task Force recommends screening for:

• Women age 65 and older
• Postmenopausal women under age 65 who have factors that increase the chance of developing osteoporosis

For men, it isn't clear yet whether regular screening is helpful. More research is needed to know for sure.

To find out if you have osteoporosis, your provider:

• Will ask about your medical history and whether you have ever broken a bone
• May do a physical exam, which could include checking for:
  • A loss of height and/or weight
  • Changes in your posture
  • Balance and gait (the way you walk)
  • Your muscle strength
• Will likely order a bone density scan
• May do a fracture risk assessment, which is a short questionnaire that helps estimate your risk of breaking a bone in the next 10 years
• Will likely order a bone density scan
• May do a fracture risk assessment, which is a short questionnaire that helps estimate your risk of breaking a bone in the next 10 years

The goals for treating osteoporosis are to slow or stop bone loss and to prevent fractures. Your provider may recommend:

• A healthy, balanced diet that includes enough calcium, vitamin D, and protein
• Lifestyle changes such as quitting smoking and limiting alcohol
• Regular physical activity including weight-bearing exercise (like walking), strength training, and balance exercises
• Fall prevention to help prevent fractures
• Medicines, such as:
  • Medicines that slow down bone loss
  • Medicines that help rebuild bone

In addition to managing your osteoporosis, it's important to avoid activities that may cause a fracture. These can include movements that involve:

• Twisting your spine, like swinging a golf club
• Bending forward from the waist, like sit ups and toe touches

You can also help reduce the risk of breaking a bone by preventing falls.

To help keep bones strong and help prevent osteoporosis, the best thing to do is to eat a healthy diet rich in calcium and vitamin D. Getting regular physical activity, limiting alcohol, and not smoking can also help.

NIH: National Institute of Arthritis and Musculoskeletal and Skin Diseases

Oxygen is a gas that your body needs to work properly. Your cells need oxygen to make energy. Your lungs absorb oxygen from the air you breathe. The oxygen enters your blood from your lungs and travels to your organs and body tissues.

Certain medical conditions can cause your blood oxygen levels to be too low. Low blood oxygen may make you feel short of breath, tired, and confused. It can also damage your body. Oxygen therapy can help you get more oxygen.

Oxygen therapy is a treatment that provides you with extra oxygen to breathe in. It is also called supplemental oxygen. It is only available through a prescription from your health care provider. You may get it in the hospital, another medical setting, or at home. Some people only need it for a short period of time. Others will need long-term oxygen therapy.

There are different types of devices that can give you oxygen. Some use tanks of liquid or gas oxygen. Others use an oxygen concentrator, which pulls oxygen out of the air. You will get the oxygen through a nose tube (cannula), a mask, or a tent. The extra oxygen is breathed in along with normal air.

There are portable versions of the tanks and oxygen concentrators. They can make it easier for you to move around while using your therapy.

You may need oxygen therapy if you have a condition that causes low blood oxygen, such as:

• COPD (chronic obstructive pulmonary disease)
• Pneumonia
• COVID-19
• A severe asthma attack
• Late-stage heart failure
• Cystic fibrosis
• Sleep apnea

Oxygen therapy is generally safe, but it can cause side effects. They include a dry or bloody nose, tiredness, and morning headaches.

Oxygen poses a fire risk, so you should never smoke or use flammable materials when using oxygen. If you use oxygen tanks, make sure your tank is secured and stays upright. If it falls and cracks or the top breaks off, the tank can fly like a missile.

Hyperbaric oxygen therapy (HBOT) is a different type of oxygen therapy. It involves breathing oxygen in a pressurized chamber or tube. That allows your lungs to gather up to three times more oxygen than you would get by breathing oxygen at normal air pressure. The extra oxygen moves through your blood and to your organs and body tissues.

HBOT is used to treat certain serious wounds, burns, injuries, and infections. It also treats air or gas embolisms (bubbles of air in your bloodstream), decompression sickness suffered by divers, and carbon monoxide poisoning.

But some treatment centers claim that HBOT can treat almost anything, including Alzheimer's disease, autism, cancer, and Lyme disease. The U.S. Food and Drug Administration (FDA) has not cleared or approved the use of HBOT for these conditions. There are risks to using HBOT, so always check with your provider before you try it.

Ozone is a gas. It can be good or bad, depending on where it is. "Good" ozone occurs naturally about 10 to 30 miles above the Earth's surface. It shields us from the sun's ultraviolet rays. Part of the good ozone layer is gone. Man-made chemicals have destroyed it. Without enough good ozone, people may get too much ultraviolet radiation. This may increase the risk of skin cancer, cataracts, and immune system problems.

"Bad" ozone is at ground level. It forms when pollutants from cars, factories, and other sources react chemically with sunlight. It is the main ingredient in smog. It is usually worst in the summer. Breathing bad ozone can be harmful. It can cause coughing, throat irritation, worsening of asthma, bronchitis, and emphysema. It can lead to permanent lung damage, if you are regularly exposed to it.

Environmental Protection Agency