Sunday, May 24, 2009
Tuesday, May 19, 2009
Lung Cancer in Non-Smokers and Women
Although lung cancer has a clear causative relationship with cigarette smoking, it can also occurs in individuals who never smoke or smoke very lightly. Interestingly, lung cancer among non-smokers is higher among women than men. In the US, 19 percent of lung cancer in women occurs in non-smokers, compared to 9 percent in men. In Asia, 60 to 80 percent of women with lung cancer never smoke [Nat Rev Cancer. 2007 Oct;7(10):778-90].
Adenocarcinoma, a subtype of lung cancer, is more common in non-smokers or light smokers.
The risk factors of lung cancer in non-smokers are:
- Secondhand smoke
- Radon
- Asbestos
- Burning coal smoke or indoor cooking oil vapor that is very common in Asia
Molecular biology of lung cancer in non-smokers is different from that of cancer in smokers. It has been observed that mutations of the epidermal growth factor receptor (EGFR) are more common in lung cancers in non-smokers. Therefore, current treatment of lung cancer in non-smokers is skewed toward the use of medications that inhibit EGFR tyrosine kinase.
Friday, May 8, 2009
Monday, May 4, 2009
Knee and Osteoarthritis (OA)
Osteoarthritis (OA), a failure of cartilage of joints, commonly affects knees. OA is no longer considered a problem of advanced aging. OA results from a complex interaction among genetics, metabolism, inflammation and mechanical factors.
Knee OA has a very strong association with obesity.
Knee joint consists of bony ends, cartilage, ligaments, and synovial fluid.
As you can see, the meniscal cartilage is sandwiched between tibia and femur. These menisci help absorb impact that is related to weight-bearing activities. The anterior and posterior cruciate ligaments help prevent knee bones from moving too much forwards or backwards.
Knee pain is the most common complaint among those who have knee OA. Knee pain can occur on inner side (medial pain), outer side (lateral pain), front side (anterior pain), or back side (popliteal pain) of the knee. Medial pain is the most common complaint of knee pain because the medial compartment of the knee has the greatest susceptibility to age-related wear and tear.
Doctors usually diagnose knee OA if patients complain of knee pain and also have at least three of the following six features:
- Age of over 50
- Morning stiffness for less than 30 minutes
- Knee bone tenderness
- Knee bone enlargement
- Clicking or grinding sound of knee bones on movements
- Absence of warm knee
Doctors may order knee X-rays to ascertain the diagnosis of OA or to rule out other knee diseases.
To treat knee OA, doctors usually start with recommendation for short-lived rest, braces, exercise, weight loss. Pain medications, needle aspiration, joint injection are next steps. Many patients may eventually need surgery. Supplements such as glucosamine and chondroitin might help but their benefits have not been proven.