Monday, June 28, 2010

Cannabidiol - a Little Known Compound in Marijuana

Cannabidiol, known as CBD, makes up about 40% of extracts from the cannabis plant. It is said to be non-psychoactive, and to counteract the psychoactive compounds known as THC. Researchers at the Canadian Department of Agriculture have found that hemp - the type of cannabis grown for fiber or in the wild in temperate climates - is low in THC and high in CBD. The plant that originated in hot climates has different genetics, and is high in THC but low in CBD. Most cannabis currently grown for street and medicinal use is the latter type, bred to be high in THC, low in CBD. This is important for growers, as CBD is known to block the effects of THC. In other words, CBD prevents a marijuana ‘high’. In addition, CBD has been found to have interesting and promising medicinal uses. Research reports on CBD are now found in the medical literature.

Pain/Sativex : Several recent studies have shown that CBD, often combined with THC, is effective against pain in patients with advanced cancer whose pain is not controlled by medicines like morphine.. Patients appreciate the lack of hallucinogenic side effects. CBD/THC extracts have also been helpful with pain and spasticity in patients with multiple sclerosis. Canada released a medicine called Sativex in 2005, which was licensed for use in patients with multiple sclerosis and cancer pain. Sativex is a mouth spray; its full effect is achieved in about an hour. It is a mixture of THC and CBD, derived from the whole plant. Sativex is currently being used in England and Spain, for multiple sclerosis, severe nerve pain, malnutrition due to AIDS, and nausea/vomiting from chemotherapy. The US FDA has approved Sativex for certain clinical trials for cancer pain.

Cancer: Research has shown that CBD may work as an anti-cancer agent with low toxicity. Researchers at CPMC in San Francisco have been working on the ability of CBD to inhibit the growth and spread of breast cancer cells in a mouse model. If the work goes well, clinical trials of CBD in human breast cancer patients may take place. CBD is also being studied as a therapy for leukemia and brain tumors known as gliomas.

Other Uses: CBD has been tested in schizophrenia, epilepsy, ulcerative colitis, and Crohn’s Disease. As yet, there are no definitive answers as to its efficacy.

CBD in the leaf: Some people with severe pain are chewing the green leaves of marijuana plants for relief. The balance between THC and CBD in the leaf is said to be helpful without giving hallucinations or a ‘high’. People differ in their response to the leaf. They find that if the leaf is green and newly harvested, they can get pain relief and stay sober, even energized, by simply chewing it. If leaves are heated or aged, however, certain effects of THC are felt, and users can become tired and feel unwell. Because of current laws on individual use, this is anecdotal information.

November Ballot: Californians will be voting in November on an initiative to legalize the recreational use of marijuana for those over 21, and to allow small residential cultivation of the plant. Local governments, but not the state government, will be able to tax and regulate marijuana. A bill is pending in the California legislature that would legalize, tax and regulate marijuana, which could generate income for the whole of California. Many proponents say that the initiative is the first step toward a rational drug policy, and will save millions by not putting users in prison. Opponents are anxious about addiction, driving under the influence, use of the drug by more teenagers, and a further proliferation of pot dispensaries. Stay tuned for a detailed discussion of the pros and cons of this important issue as November approaches.
Sadja Greenwood, MD, MPH back issues at on this blog

Monday, June 21, 2010

Cell Signaling via Hormones

You probably have a cell phone and you may have a computer; many of you contact the world and your friends with calls, texting, email, facebook, twitter, and old-fashioned talk. Within your body, your cells are connected in a much more intricate way, constantly signaling each other through the bloodstream, nerves, and direct or short distance contact. What goes on between your 10-100 trillion cells is amazing; no cell can live in isolation – survival depends on an elaborate intercellular communication network that coordinates the growth and metabolism of cells in diverse organs. In this column I will outline the function of endocrine glands that produce hormones, chemicals that circulate in the bloodstream and affect cells and organs throughout the body.

Endocrine Glands in the Brain
Hypothalamus: this tiny key gland, located near the center of the brain, regulates the anterior pituitary, increasing or decreasing its hormonal output. It regulates the autonomic nervous system, body temperature, and many other functions.
Anterior pituitary: this gland regulates growth hormone, the thyroid gland, the adrenal gland, the ovaries and testes, and milk synthesis in the breast
Posterior pituitary: this gland regulates uterine contraction, milk letdown, and kidney functions in men and women..
Pineal gland: located behind the eyes, the pineal regulates the sleep-wake cycle via the hormone melatonin. Bright light suppresses melatonin and wakes you up, darkness promotes melatonin secretion and puts you to sleep.

With all this happening in glands of the brain, it is clearly important to keep your brain safe and healthy. My advice – avoid brain injury by always wearing helmets for riding bikes or horses, and be very careful on motorcycles. Don’t hit soccer balls with your head, and don’t allow your children to do so. Football and boxing often injure the brain. Avoid drugs and excess alcohol. Treat high blood pressure, to avoid a stroke. Exercise daily and eat healthfully.

Some other Endocrine Glands
Thyroid Gland: located in the lower neck, the thyroid secretes hormones known as T3 and T4, that stimulate the body to consume oxygen, use energy, and thereby increase the rate of metabolism. They also promote protein synthesis. Calcitonin, produced by specialized cells in the thyroid gland, stimulates bone construction.
Adrenal Glands: Located above the kidneys, these glands put out cortisol, which stimulates glucose production, suppresses inflammation, and inhibits immune responses. They also produce aldosterone, which increases blood volume and blood pressure. The adrenals produce androgens, which give women increased facial hair, and become a source of estrogen for women after menopause. The inside of the adrenal glands produce epinephrine – the fight-or-flight hormone, which also increases blood pressure, heart rate and muscular readiness.
Pancreas: Located below the stomach and adjacent to the liver, this organ secretes insulin, which promotes the uptake of glucose from the bloodstream, enabling cells to use it for energy, and the liver to store it as glycogen. The pancreas also secretes glucagon, which acts in the opposite direction, increasing blood glucose levels when needed for activity.
Ovary: Estrogen, produced from pre-puberty to menopause, stimulates the growth of the uterus and its lining, as well as breast cells. It has many effects throughout the body and brain. Estrogen increases the secretion of cholesterol in bile, which is why women in their reproductive years are more prone to gall stones. Progesterone, produced by ovaries in the second half of the menstrual cycle, and during pregnancy, helps to sustain pregnancy. It also has favorable effects on the thyroid, bones, teeth, gums, joints and tendons.
Testis: Androgens from the testes, mainly testosterone, increase muscle mass and strength, deepen the voice and promote the growth of bodily hair. Testes also secrete some estrogen, which helps with bone strength.

There are other hormone secreting organs in the body as well, including the heart, kidneys, skin, gastrointestinal tract, and fat. Imagine all these hormones circulating in the bloodstream, influencing your trillions of cells. It gives me a feeling of awe - of evolution, of our closeness to other animals, who share these hormones, and of the wisdom of our bodies. Stay as healthy as you can, and your body should reward and amaze you with its intricate workings.
Sadja Greenwood, MD, MPH
Back issues at on this blog

Tuesday, June 8, 2010

Go to Health - Save Your Eyesight

Sans teeth, sans eyes, sans taste, sans everything” wrote Shakespeare in As You Like It about the final stage of life. All the world’s a stage is great poetry, but certain steps not available in Shakespeare’s time can preserve your eyesight into old age. (As far as teeth are concerned, visit your dentist! I’ll take up the tooth issue in a later column.)

Glaucoma: A regular checkup by an eye doctor to screen for increased pressure in the fluid of your eyes will detect glaucoma, an eye disease leading to progressive loss of sight. Treatment with medicinal eye drops and laser surgery is effective. Most people should start eye checks at age 35- 40, and follow the testing advice of their eye doctor. Older people, African Americans, Hispanics, and those with a family history of glaucoma are more at risk.

Cataracts are changes in the lens inside the eye that focuses light on the retina (in the back of the eye). When the lens becomes cloudy, vision is impaired. Some causes of cataracts can be avoided – excessive exposure to UV light – wear sunglasses on bright days, and when on the water or in the snow. Start using sunglasses early in life. Don’t smoke! Smoking is a risk factor for cataracts. Stay active and of normal weight, to avoid diabetes, another risk factor for cataracts. Cataracts can be successfully treated with surgery, with the implantation of a new lens.

Macular Degeneration is a deterioration of the central portion of the retina – the interior layer of the eye that transmits signals into the optic nerve. With the macula we see detail – to read, recognize faces, do crafts, and get around safely. There is a dry and a ‘wet’ form of macular degeneration – the wet form can give rapid loss of vision due to blood vessel leaking that scars the retina. Macular degeneration is more common among lightly pigmented people (‘whites’), in smokers, in people who are obese, and in those with a family history of the disease.

Prevention of macular degeneration is important and the following steps are part of a program for healthy living that you already know. The health of your eyes is not separate from the rest of your body:

*Stop smoking! It’s a risk factor for blindness.

*Eat lots of vegetables, especially leafy greens. Kale, spinach. collard greens, broccoli, green peas and Brussels sprouts are all good sources of the antioxidants lutein and zeaxanthin that are especially helpful for the retina. Prolonged cooking decreases the bioavailability of lutein, so steam your greens lightly, and eat a raw salad daily. Egg yolk is another good source of these antioxidants. Chickens that have been out in green pastures lay eggs with the deepest orange yolks, with more lutein.

*Eat fish and/or take fish oil supplements - the omega-3 fatty acids may reduce the risk. A 2009 study at the National Eye Institute in Bethesda showed that a diet with high levels of omega-3 fatty acids resulted in slower progression of macular degeneration (in mice), with improvement in some lesions. The mice also had lower levels of inflammatory makers, which may explain the protective effect.
*Exercise and maintain a healthy weight. A study from the University of Wisconsin found that people who were physically active were markedly less likely to develop macular degeneration.

*Wear sunglasses – they protect the retina

*See your eye doctor regularly

There is great beauty in this world, despite its terrible problems. To enjoy this visual beauty into old age, follow the steps in the column.
Sadja Greenwood, MD, MPH Leave me a message!