Month: May 2010

My First Physics Teacher

I always liked math. It took work, but it came pretty easily to me most of the time. I liked being able to work out the abstract problems and get the right answer. I liked getting positive feedback and encouragement from my teachers, as one of the top math students. Then I took physics senior year in high school. Suddenly sin(x) was equal to x, if x was a small angle. Suddenly all the nice rules of math were up for grabs and approximations had to be devised to solve the problems. Initially I found this to be hard. Sometimes I still do, even as a working research physicist. Because suddenly creativity and insight were a major part of my science education.

I still remember my first physics teacher. He had been working in industry for years prior to his new teaching career, so he was a “real” physicist instead of just a high school teacher. The lesson that I remember the most was about lenses. Before the teacher lectured on the subject in class, he handed out to each group a lens and a flashlight. We were suppose to devise experiments to determine the unknown properties of the lens. Most people tried various experiments inside the dark classroom, shining the flashlight on the lens (with only a vague understanding of what we were even looking for). A few people also went outside to use the sun as a very distant source of light. Very few, if any, of us figured out the lens equation or imaging properties of the lens. However, we ALL paid attention to the next lecture on lenses. Our teacher challenged and engaged us. He made us think, instead of just having us solve cookbook problems for the upcoming tests. My first introduction to physics was hard but interesting. And when I went off to college, it gave me a head start in my physics career. If I could grade my high school physics teacher, I’d give him an A.

A lot of women have stories about their science and math teachers — what did they do right or wrong? How did they influence your career, education and life? Now you have the chance to share your stories. Under the Microscope is a blog about women and science education. They collect stories from women involved in science, technology, engineering and math with the goal of publishing a survival guide for young women in science.  In the month of May, Under the Microscope is sponsoring a project to get women to write a “report card” for their early math and science teachers. Hurry and add your stories by May 31.

FDA Approves Prostate Cancer Vaccine

How much is 4 months of your life worth? Some men with advanced prostate cancer will be able to find out, as a result of a new drug developed byDendreon Corporation. This drug, Provenge (sipuleucel-T), was recently approved by the FDA to treat advanced prostate cancer.

They are calling Provenge a “vaccine,” but it doesn’t work like vaccines against infections such as measles or mumps. This vaccine is used to treat advanced prostate cancer rather than prevent it. It works by using the patient’s own immune system. The vaccine is made by taking a sample of the patient’s blood, removing the white blood cells, and exposing them to the Dendreon PAP-GM-CSF protein. This specialized fused protein includesprostatic acid phosphatase (PAP), which is an enzyme produced by the prostate and found at increased levels in prostate cancer. Once the vaccine is made, the cells are then infused back into the patient’s vein. The patient receives three of these treatments, 2 weeks apart. Basically the treated cells help stimulate the patient’s immune system to attack his prostate cancer.

The FDA approval of this new vaccine was largely based on the results of Dendreon’s recently completed Provenge Phase III Trial. This was a randomized clinical trial involving 512 men between the ages of 40 and 91 years, of which 341 men received Provenge and 171 men received a placebo. All the men had advanced prostate cancer that was unresponsive to hormone therapy. The common side effects of the Provenge were reported to be minor — such as chills (54%), fevers (29%), and headaches (16%) — and only lasted a couple days after infusion. The men that received the Provenge on average lived 4.1 months longer than the men that took the placebo (25.8 months v.s. 21.7 months). This is a significant break through for men with advanced prostate cancer, who have few treatment options.

There was no evidence that Provenge slowed progression of the disease. How the drug can improve survival rate without slowing disease progression is not clear yet. The FDA approval of Provenge is also limited to only men with prostate cancer (that has progressed despite hormone treatments) with only minimal symptoms at the time of treatment. So this vaccine is not for everyone with prostate cancer. However, it is the first active immunotherapy to demonstrate improvement in overall survival for advanced prostate cancer. As a “proof of concept” drug, it is expected to spark new interest in the development of drugs based on similar principles.

Other prostate cancer vaccines are also in development, including PROSTVAC-VF that uses a genetically modified virus containing prostate-specific antigen. The patient’s immune system is expected to respond to the virus by recognizing and killing the cancer cells with prostate-specific antigen. A randomized phase II clinical study of Therion Biologic’s PROSTVAC-VF was published this January. It involved 122 patients with metastatic prostate cancer who did not respond to hormone therapy, of which 82 received the vaccine and 40 the placebo. This study also demonstrated an increase in survival rate for those taking the vaccine, in this case an average of 8.5 months. This study is small, but the researchers are planning a phase III trial with 600 patients to further evaluate the drug’s effectiveness.

So lets hope that these new drugs represent only the first step in finding effective new ways to treat cancers. In the future, hopefully we’ll be able to “turn on” the body’s own defense mechanisms to treat or prevent many types of cancer.

Making Diesel at Solar Plants

Normally biofuels and solar power are considered to be competing alternative energy sources. However, some researchers are merging these technologies, trying to use the best of both to create “solar fuels.”  This includes the researchers at a small start-up company from Cambridge Massachusetts, Joule Unlimited, which was recently listed as one of the world’s ten most important emerging technologies by MIT’s Technology Review 2010 TR10. It was also selected as part of the TR50 in February, the only company besides Google that was chosen for both honors.

Joule Unlimited has manipulated and designed genes to create photosynthetic microorganisms. These microorganisms use energy from the sun to convert carbon dioxide and water directly into ethanol or hydrocarbon fuels (such as diesel). The photosynthetic microorganisms are designed with a genetic switch that limits growth. They are allowed to multiply for a couple days, then the genetic switch is flipped to divert their energy into fuel production. The microorganisms excrete the fuel, which is chemically separated and collected using conventional technologies.

The goal of this direct, continuous process is to achieve high fuel production with minimal land use. The microorganisms are grown in water inside transparent bioreactors, where they are circulated to make sure that all the microorganisms are exposed to sunlight. Different kinds of non-potable water can be used in this process, including brackish water, waste water or seawater. The microorganisms are fed concentrated carbon dioxide and other nutrients. The long term hope is to use carbon dioxide from polluting facilities such as coal plants.

Joule Unlimited claims to have specifically designed both their microorganisms and bioreactors to work in harmony together, in order to maximize fuel production. For instance, the company carefully designed the bioreactor to keep the heat within the limits required by their microorganism. In the long term, the company is hoping to produce 25,000 gallons per acre per year of ethanol and 15,000 gallons per acre per year of diesel at the competitive price of $30 per barrel. They are planning to scale up from demonstration facilities to building a commercial facility in 2012, in order to start producing diesel in 2013. However, their engineers still need to improve the performance of the microorganism to meet these targets, as well as address whatever issues arise during scale-up.

Joule Unlimited isn’t the only one working in this research area. Others working on solar fuels include:  (1) Synthetic Genomics in La Jolla, CA, (2) BioCee in Minneapolis, MN, and (3) University of Minnesota BioTechnology Institute, St. Paul, MN. Hopefully the race is on, and the winner will be all of us.

Joule facility
A diagram of how a Joule facility would work with bioreactors growing micro organisms with sunlight and CO2 in water. A separator removes the end product -- liquid fuel or chemicals. (Courtesy of Joule Unlimited)

Want A Net-Zero Energy Home?

Berkeley Lab presents 3 talks on “The House of the Future.” Come get a preview of tomorrow’s zero-energy home with cool roofs, smart windows, and computer-driven control systems. These talks are for a general audience, on May 10 at 7-9 p.m. at the Berkeley Repertory Theatre. Free admission. More information at http://www.lbl.gov/LBL-PID/fobl/.

Risk of Invasive Breast Cancer Predicted

Way too many of my women friends have suffered through breast cancer diagnosis, starting with a close friend who died of breast cancer in her early 30s. Her death inspired me to change careers, in hopes of developing better ways to detect and stage breast cancer. Although the focus of my work has now moved on to other medical imaging areas, I still pay particular attention to new breast cancer research.

It seems like there are reports on breast cancer research in the news daily. But my eye was particularly caught by an article published online on April 28, 2010 in the Journal of the National Cancer Institute. A group of researchers, from UCSF Helen Diller Family Comprehensive Cancer Center, are now able to predict whether women with ductal carcinoma in situ are at high or low risk of developing subsequent invasive cancer.

Ductal carcinoma in situ (DCIS) is the most common type of non-invasive breast cancer. The American Cancer Society estimates that about 60,000 women are diagnosed with DCIS in the U.S. each year. This cancer starts in the milk ducts. It is called non-invasive because it hasn’t spread beyond the milk ducts into any normal surrounding breast tissue. DCIS isn’t life-threatening and it rarely leads to death from breast cancer, but having DCIS can increase your risk of developing an invasive breast cancer in the future. Approximately 11 out of 100 women diagnosed with DCIS and treated with a lumpectomy only go on to develop invasive cancer within 8 years, and about the same number go on to develop subsequent DCIS within 8 years. That means that the majority of such women have no further tumors, but these women typically still go through some form of aggressive treatment.

So we really need a way to predict which women with DCIS have a high risk of developing subsequent tumors. The UCSF scientists report that they’ve discovered a method to do just that. They collected and analyzed data for 1162 women aged 40 years or older, who were diagnosed with DCIS and treated with a lumpectomy alone in the San Francisco Bay Area. They followed and measured clinical, histopathologic, and molecular characteristics of subsequent tumors for this large population (from 63 hospitals) for 8 years.

They found that the risk of subsequent invasive cancer was significantly increased among women whose initial DCIS was detected by palpation compared with those detected by mammography. They also found that DCIS lesions that were “triple positive” for the expression of biomarkers p16, COX-2and Ki67 had an even higher risk of subsequent invasive cancer. However, these factors were not associated with increased risk of subsequent DCIS. An independent set of biomarker expression and conditions was identified for increased risk of subsequent DCIS, with the lowest risk group having disease-free surgical margins of 10 mm or larger.

Based on their findings, the UCSF scientist were able to stratify the women into 4 categories for risk of subsequent invasive cancer — Lowest (17%), Low (27%), Intermediate (28%) and High (28%). The lowest risk group had only a 4% risk of developing invasive cancer within 8 years, whereas the high risk group had a 20% risk. A similar stratification was performed for risk of subsequent DCIS with similar results.

Hopefully this new method of predicting risk for subsequent cancers will help women with DCIS chose the proper treatment. Karla Kerlikowske, the lead author, states “It will lead to a more personalized approach to treatment. As many as 44 percent of the patients (i.e., lowest and low risk groups) with DCIS may not require any further treatment, and can rely on surveillance.”