You've probably heard about some of the breakthroughs in personal genome sequencing, where companies take a look at your DNA and send back your risk profile. That can be confusing information to have (check out this post from Quest blogger Dr. Barry Starr for his take on it). But there's a flip side to all this genetic research that doesn't have to do with risk: personalized medicine. That's where doctors can customize medical treatments to fit your genetic profile.

Right now, there are only a handful of drugs that are labeled with genetic information, so doctors can take it into consideration. (Here's an article from the New York Times that gives an overview).  But that doesn't mean existing medications are left out.  I spent some time with Deanna Kroetz in this story, who studies pharmacogenomics at UC San Francisco.  She explained that differences in our DNA can cause some of us to process drugs at different rates. We all metabolize drugs with enzymes in the liver, but based on expression of our DNA, we may have different levels of enzymes or our enzymes may not function as well.

There are plenty of other things that affect how we process drugs, like our diet or other drugs we're taking. But these genetic differences mean some people metabolize drugs quickly and others metabolize them slowly. One example that many people are familiar with is codeine.  Codeine is converted into morphine by our bodies and it's the morphine that actually has an effect — but that conversion depends on a particular enzyme. Some people have very low levels of the enzyme that's needed, so codeine doesn't do much for them.

They're also studying another drug response mechanism at UCSF and it has to do with our cells. Many drugs have to go inside our cells in order to have an effect, but if you think back to high school biology, you might remember that cells are protected by membranes.  It takes transporters – those special gatekeepers sitting on the cell membranes — to allow things in.  They also can spit things out of cells.

I spent some time in the lab with Rachel LaFond, a graduate student at UCSF.  She was running experiments on one particular transporter known as ABCG2. This transporter is particularly good at spitting things out of cells. Normally its job is to kick toxins out, but some cancers have been able to hijack this machinery.  Cancer cells with an over expression of this transporter can spit out chemotherapy drugs, which means they aren't helping the patient.  LaFond is working to understand this variation better, so they could one day develop a genetic test for it.

Listen to the Personalized Medicine radio report online.

(Editor's note: Today we've got a guest post from Nick Vidinsky, Producer of KQED's Health Dialogues)

Hi everybody. I want to let the QUEST community know that over at KQED’s Health Dialogues, we just launched a new project, called Healthy Ideas: Californians Weigh In on Health Care Reform.

In his 100th day press briefing a few days ago, President Obama reiterated his desire to enact health care reform by the end of 2009. The President has also put out a call to all Americans to submit our ideas on just how to do that. So, Health Dialogues decided that we’d let Washington know what Californians think.

Is the cost of new medical technologies worth the potential health benefits? What can we do to eliminate health disparities across socioeconomic backgrounds? Should everyone be required to purchase health insurance?

Healthy Ideas is a conversation among academics, health care professionals, policy think tanks and the general public about what kind of health care reform California wants and needs. During the next two months, you can join the dialogue by reading our authors’ weekly posts, rating them and contributing your own thoughts and questions. At the end of the project, on July 1, we’ll summarize your ideas and deliver them to California’s representatives in Washington, as well as the Obama Administration, Senate Finance Committee Chairman Max Baucus and Senate Committee on Health, Education, Labor and Pensions Chairman Edward Kennedy.

To contribute your thoughts and let Washington know what kind of health care reform you want, join the dialogue at Healthy Ideas: Californians Weigh In on Health Care Reform.

Thanks!
Nick Vidinsky
Producer, Health Dialogues

Scientists gather samples on the ocean floor.
Credit: Roger Linington.There's nothing new about looking to nature to cure disease – we've been doing it for thousands of years, with good results. (Two recent examples: The active ingredient in aspirin was first identified in the bark of the willow tree. And we have the Pacific yew tree to thank for one of the strongest anti-cancer drugs out there, Taxol.)

What's different about the work being done at the UC Santa Cruz Chemical Screening Center is that it a) looks to a largely unexplored medical resource: the ocean, and b) uses robots, rather than "forlorn-looking grad students" (to quote Center director Scott Lokey) to run the tests.

Here's a video I shot of one of those robots in action, with Lokey narrating.

One thing that didn't make it into the piece is that these researchers — including Lokey and Roger Linington — aren't just studying every disease they can think of. They focus on the diseases that commercial drug companies tend to neglect because there's so little profit in treating them – things like African sleeping sickness and cholera. So far, they're seeing progress on both, as well as breast cancer.

Listen to the Medicine from the Ocean Floor radio report online and check out images from this story in an online slideshow.

Artificial Turf. Credit: Anthony V. ThompsonIt's easy to get scared. You look around the Oakland office of the Center for Environmental Health, and lead is everywhere. Piles of toys that are loaded with lead. Lunch boxes and kids' backpacks that have tested positive for high levels of lead. Samples of artificial turf.

And that's just the beginning. Lead has been found in venetian blinds, in pens, in the glaze of ceramic cups and bowls. It has been found in imported candies. And one Mexican folk remedy to cure stomachaches has landed a number of children in the hospital recently – a packet of powder that is almost entirely lead.

Since the effects of lead are cumulative, all those points of contamination add up.

Children's developing brains and central nervous systems are most susceptible to damage from ingesting lead. That's why a new federal standard for lead in children's products was recently put in place. And that's why the Center for Environmental Health, for one, focuses on products that come in contact with children on a daily basis.

The amount of lead in artificial turf, by itself, is unlikely to cause lead poisoning. And the same is true for the amount of lead found in lunch boxes, or in children's jewelry. But medical experts say that if kids play on artificial turf in the morning, distractedly put a charm bracelet in their mouths during class, and eat food from a lunch box with lead embedded in the vinyl – then those kids are at risk for lead impairment, such as a loss of IQ points, a sign of brain damage. For more, listen to the QUEST Radio story, or check our photos below.

Soon after Barack Obama is sworn in as President next week, he is expected to reverse George Bush’s executive order limiting embryonic stem cell research. Scientists say their research has been stifled by restricting them to existing stem cell lines. The resulting boom in this cutting-edge medical technology will benefit California's research institutes in a big way.

Researchers call stem cell technology a "revolution" in medicine, along the lines of the development of antibiotics in the 1940s, or the manufacturing of insulin and other therapies from recombinant DNA breakthroughs.

But why do stem cells offer such promise?

Robert Klein, chair of the governing board for the California Institute of Regenerative Medicine (the state stem-cell agency created by Proposition 71), says that the recombinant DNA revolution in the 1970s saved the life of his son, and that the potential for saving lives is even greater with stem cell work.

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Stem cell technology has only existed for a decade. And despite the Presidential ban on use of new lines of embryonic stem cells, the advances in research have happened quickly. And, according to Deepak Srivastava, Director of Cardiovascular Research at the UCSF Gladstone Institute, the many possible applications of stem cell work will be seen in the short term (over the next few years) and long term (regeneration of damaged organs could happen in 7 to 10 years, he says).

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Dr. Srivastava says, in the case of one of his patients, five-month-old Ryder Ortiz, stem cell technology could have been a godsend. And it might still BE a godsend, he adds. Ryder was born without a left ventricle, the heart chamber that shoots blood into the body. With stem cell technology, it may become possible to grow a new ventricle, and that would’ve been a huge boon to the infant Ryder.

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But here's the thing: Doctors jerry-rigged Ryder's circulatory system, and it's a process that works – until the patient hits his teen years. In many cases, that’s when the re-worked circulatory system fails. Now, if Dr. Srivastava's estimate is correct, and the technology develops in the next 7 to 10 years, that will be just in time for Ryder Ortiz, who will be inching nearer to adolescence at that time.

Listen to the New Life for Embryonic Stem Cell Research radio report online.

Bobby is more likely to be gay than Greg.

Last blog I talked about some studies that link homosexuality and genes. The most powerful studies are those that compare identical twins to fraternal twins. These studies show that both twins in an identical pair are more likely to be gay than are both twins in a fraternal pair. Since identical twins have the same DNA, this suggests that something genetic is going on.

But no study showed that if one identical twin was gay, then the other one was always gay as well. We'd expect both twins in an identical twin pair to share a purely genetic trait 100% of the time. Because they don't, the environment definitely plays a role. But not like you might think.

By environment I don't mean certain family situations (although these sorts of factors probably contribute as well). What I am referring to are environmental factors that can affect brain development. Factors like viruses, hormones, or maybe even antibodies.

We know, for example, that the more older brothers a man has, the more likely he is to be gay. Even if he doesn't live with the older brothers.

This suggests that something biological is going on. It is as if the mother's body remembers how many sons she has had. One way this might happen is through her immune system.

Perhaps when a mother has a son, she makes antibodies to something having to do with carrying a male child. The more sons she has, the more antibodies she makes. At some point, she makes enough antibodies to affect brain development and the younger son is now gay.

Of course, not every youngest son is gay– he is just more likely to be homosexual. Other factors have been reported to increase the chances that someone is gay too. These include being left handed, having a counter-clockwise hair whorl and maybe even different finger lengths. All of these traits are associated with differences in brain development.

There are apparently many paths to a homosexual brain. This isn't surprising as human sexuality is much too complex to be due to a single gene or environmental factor. Most likely, it is the result of many factors all working together.

Some gay men may have inherited genes that made environmental factors more likely to affect their sexuality. And some gay men may have been exposed to multiple environmental effects that affected their sexuality despite their genes.

I think you can appreciate how these kinds of complex interactions can make finding "gay" genes incredibly complicated. And why it is hard to pinpoint the environmental effects that contribute to becoming homosexual as well.

Dr. Barry Starr is a Geneticist-in-Residence at The Tech Museum of Innovation in San Jose, CA.

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