Secondhand smoke damages lungs, MRIs show

Researchers use MRI scanner to image damage in the lung due to second-hand smoke.They presented this work at RSNA 2007

K.S.Parthasarathy

Public release date: 26-Nov-2007


Contact: Rachel Salis-Silverman
Salis@email.chop.edu
267-426-6063
Children's Hospital of Philadelphia
Secondhand smoke damages lungs, MRIs show
The apparent diffusion coefficient (ADC) measures lung injury, indicated by different colors.
Click here for more information.

It’s not a smoking gun, but it’s smoking-related, and it’s there in bright medical images: evidence of microscopic structural damage deep in the lungs, caused by secondhand cigarette smoke. For the first time, researchers have identified lung injury to nonsmokers that was long suspected, but not previously detectable with medical imaging tools.

The researchers suggest that their findings may strengthen public health efforts to restrict secondhand smoke.

“We used a special type of magnetic resonance imaging to find these structural changes in the lungs,” said study leader Chengbo Wang, Ph.D., a magnetic resonance physicist in the Department of Radiology at The Children’s Hospital of Philadelphia. “Almost one-third of nonsmokers who had been exposed to secondhand cigarette smoke for a long time developed these structural changes.” Formerly at the University of Virginia, Wang collaborated with radiology researchers at that institution, where they acquired the MRIs from adult smokers and nonsmokers.

Wang presented the team’s findings in Chicago at the annual meeting of the Radiological Society of North America. Although the participants in the research study were adults, Wang said the results have implications for the 35 percent of American children who live in homes where regular smoking occurs.

The researchers studied 60 adults between ages 41 and 79, 45 of whom had never smoked. The 45 non-smokers were divided into groups with low and high exposure to secondhand smoke; the high-exposure subjects had lived with a smoker for at least 10 years, often during childhood. The 15 current or former smokers formed a positive control group.

The research team prepared an isotope of helium called helium-3 by polarizing it to make it more visible in the MRI. Researchers diluted the helium in nitrogen and had research subjects inhale the mixture. Unlike ordinary MRIs, this MRI machine measured diffusion, the movement of helium atoms, over 1.5 seconds. The helium atoms moved a greater distance than in the lungs of normal subjects, indicating the presence of holes and expanded spaces within the alveoli, tiny sacs within the lungs.

The researchers found that almost one-third of the non-smokers with high exposure to secondhand smoke had structural changes in their lungs similar to those found in the smokers. “We interpreted those changes as early signs of lung damage, representing very mild forms of emphysema,” said Wang. Emphysema, a lung disease that is a major cause of death in the U.S., is commonly found in heavy smokers.

The researchers also found a seemingly paradoxical result among two-thirds of the high-exposure group of non-smokers—diffusion measurements that were lower than those found in the low-exposure group. Although these findings require more study, said Wang, they may reflect a narrowing in airways caused by early stages of another lung disease, chronic bronchitis.

“To our knowledge, this is the first imaging study to find lung damage in non-smokers heavily exposed to secondhand smoke,” said Wang. “We hope our work strengthens the efforts of legislators and policymakers to limit public exposure to secondhand smoke.”

###

The study received financial support from the National Heart, Lung and Blood Institute, the Flight Attendant Medical Research Institute, the Commonwealth of Virginia Technology Research Fund, and Siemens Medical Solutions.

Wang’s co-authors were Talissa A. Altes, M.D., and Kai Ruppert, Ph.D., now of the Children’s Hospital Radiology Department; and G. Wilson Miller, Ph.D., Eduard E. deLange, M.D., Jaime F. Mata, Ph.D., Gordon D. Cates, Jr., Ph.D., and John P. Mugler III, Ph.D., all of the University of Virginia Department of Radiology. Drs. Wang, Altes, and Ruppert were previously at the University of Virginia as well.

About The Children's Hospital of Philadelphia: The Children's Hospital of Philadelphia was founded in 1855 as the nation's first pediatric hospital. Through its long-standing commitment to providing exceptional patient care, training new generations of pediatric healthcare professionals and pioneering major research initiatives, Children's Hospital has fostered many discoveries that have benefited children worldwide. Its pediatric research program is among the largest in the country, ranking third in National Institutes of Health funding. In addition, its unique family-centered care and public service programs have brought the 430-bed hospital recognition as a leading advocate for children and adolescents. For more information, visit http://www.chop.edu.

[ Back to EurekAlert! ] [ Print Article | E-mail Article | Close Window ]

Post-treatment PET scans can reassure cervical cancer patients

PET scanner is a very powerful tool which can pinpoint secondary cancers , if any, in patients who underwent radiation treatment

K.S.Parthasarathy




Public release date: 20-Nov-2007


Contact: Gwen Ericson
ericsong@wustl.edu
314-286-0141
Washington University in St. Louis
Post-treatment PET scans can reassure cervical cancer patients

St. Louis, Nov. 20, 2007 — Whole-body PET (positron emission tomography) scans done three months after completion of cervical cancer therapy can ensure that patients are disease-free or warn that further interventions are needed, according to a study at Washington University School of Medicine in St. Louis.

"This is the first time we can say that we have a reliable test to follow cervical cancer patients after therapy," says Julie K. Schwarz, M.D., Ph.D., a Barnes-Jewish Hospital resident in the Department of Radiation Oncology. "We ask them to come back for a follow-up visit about three months after treatment is finished, and we perform a PET scan. If the scan shows a complete response to treatment, we can say with confidence that they are going to do extremely well. That's really powerful."

Schwarz and colleagues published their study in the Nov. 21, 2007 issue of the Journal of the American Medical Association (JAMA).

Without a test like PET, it can be difficult to tell whether treatment has eliminated cervical tumors, Schwarz says. That's because small tumors are hard to detect with pelvic exams, and overt symptoms, such as leg swelling, don't occur until tumors grow quite large. Furthermore, CT and MRI scans often don't differentiate tumor tissue from surrounding tissues, Pap tests can be inaccurate because of tissue changes induced by radiation therapy, and no blood test exists to detect the presence of cervical cancer.

Cancerous tumors glow brightly in the PET scans used in the study, called FDG-PET scans, which detect emissions from radioactively tagged blood sugar, or glucose. Tumor tissue traps more of the glucose than does normal tissue, making tumors readily discernable.

Not only can post-treatment PET scans reassure those patients whose tumors respond well to therapy, they can also identify those patients whose tumors have not responded so that their physicians can explore other treatment options before the cancer advances further. These options can include surgery to remove tissue, standard chemotherapy or experimental therapies available through clinical trials.

"Follow-up PET scans can also be very useful tools for physicians conducting clinical trials of new therapies," Schwarz says. "Our study has shown that the scans are predictive of long-term survival. Using PET scans, clinical researchers can get an early readout of how effective experimental treatments might be."

Schwarz and colleagues also have a project to compare follow-up PET results with tumor biology to find out why some tumors don't respond well to therapy. In a study that won her a Resident Clinical Basic Science Research Award from the American Society for Therapeutic Radiation and Oncology, a global organization of medical professionals, Schwarz found differences in gene activity between tumors from patients that responded well and those that had persistent disease. Ongoing research will look for the significance of these differences.

The study's senior author, Perry Grigsby, M.D., professor of radiation oncology, of nuclear medicine and of obstetrics and gynecology and a radiation oncologist with the Siteman Cancer Center at Washington University School of Medicine and Barnes-Jewish Hospital, has overseen a patient database that now has PET images and tumor samples from hundreds of cervical cancer patients.

"We have a tremendous database of PET images collected from patients in the department since 1998," Schwarz says. "We want to combine these results with analyses of tumor biopsies so that we can more effectively choose additional therapies for patients who haven't responded to the initial treatment."

###

Schwarz JK, Siegel BA, Dehdashti F, Grigsby PW. Association of posttherapy positron emission tomography with tumor response and survival in cervical carcinoma. Journal of the American Medical Association, November 21, 2007.

Funding from the Department of Radiology and the Department of Radiation Oncology at Washington University School of Medicine in St. Louis supported this research.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.

Siteman Cancer Center is the only federally-designated Comprehensive Cancer Center within a 240-mile radius of St. Louis. Siteman Cancer Center is composed of the combined cancer research and treatment programs of Barnes-Jewish Hospital and Washington University School of Medicine. Siteman has satellite locations in West County and St. Peters, in addition to its full-service facility at Washington University Medical Center on South Kingshighway.

Remote-control nanoparticles deliver drugs directly into tumors

Public release date: 16-Nov-2007

Contact: Elizabeth Thomson
thomson@mit.edu
617-258-5402
Massachusetts Institute of Technology
MIT: Remote-control nanoparticles deliver drugs directly into tumors

CAMBRIDGE, MA--MIT scientists have devised remotely controlled nanoparticles that, when pulsed with an electromagnetic field, release drugs to attack tumors. The innovation, reported in the Nov. 15 online issue of Advanced Materials, could lead to the improved diagnosis and targeted treatment of cancer.

In earlier work the team, led by Sangeeta Bhatia, M.D.,Ph.D., an associate professor in the Harvard-MIT Division of Health Sciences & Technology (HST) and in MIT's Department of Electrical Engineering and Computer Science, developed injectable multi-functional nanoparticles designed to flow through the bloodstream, home to tumors and clump together. Clumped particles help clinicians visualize tumors through magnetic resonance imaging (MRI).

With the ability to see the clumped particles, Bhatia’s co-author in the current work, Geoff von Maltzahn, asked the next question: “Can we talk back to them?”

The answer is yes, the team found. The system that makes it possible consists of tiny particles (billionths of a meter in size) that are superparamagnetic, a property that causes them to give off heat when they are exposed to a magnetic field. Tethered to these particles are active molecules, such as therapeutic drugs.

Exposing the particles to a low-frequency electromagnetic field causes the particles to radiate heat that, in turn, melts the tethers and releases the drugs. The waves in this magnetic field have frequencies between 350 and 400 kilohertz—the same range as radio waves. These waves pass harmlessly through the body and heat only the nanoparticles. For comparison, microwaves, which will cook tissue, have frequencies measured in gigahertz, or about a million times more powerful.

The tethers in the system consist of strands of DNA, “a classical heat sensitive material,” said von Maltzahn, a graduate student in HST. Two strands of DNA link together through hydrogen bonds that break when heated. In the presence of the magnetic field, heat generated by the nanoparticles breaks these, leaving one strand attached to the particle and allowing the other to float away with its cargo.

One advantage of a DNA tether is that its melting point is tunable. Longer strands and differently coded strands require different amounts of heat to break. This heat-sensitive tuneability makes it possible for a single particle to simultaneously carry many different types of cargo, each of which can be released at different times or in various combinations by applying different frequencies or durations of electromagnetic pulses.

To test the particles, the researchers implanted mice with a tumor-like gel saturated with nanoparticles. They placed the implanted mouse into the well of a cup-shaped electrical coil and activated the magnetic pulse. The results confirm that without the pulse, the tethers remain unbroken. With the pulse, the tethers break and release the drugs into the surrounding tissue.

The experiment is a proof of principal demonstrating a safe and effective means of tunable remote activation. However, work remains to be done before such therapies become viable in the clinic.

To heat the region, for example, a critical mass of injected particles must clump together inside the tumor. The team is still working to make intravenously injected particles clump effectively enough to achieve this critical mass.

“Our overall goal is to create multifunctional nanoparticles that home to a tumor, accumulate, and provide customizable remotely activated drug delivery right at the site of the disease,” said Bhatia.

###

Co-authors on the paper are Austin M. Derfus, a graduate student at the University of California at San Diego; Todd Harris, an HST graduate student; Erkki Ruoslahti and Tasmia Duza of The Burnham Institute in La Jolla, CA; and Kenneth S. Vecchio of the University of San Diego.

The research was supported by grants from the David and Lucile Packard Foundation, the National Cancer Institute of the National Institutes of Health. Dervis was supported by a G.R.E.A.T fellowship from the University of California Biotechnology Research and Educational Program.

Written by Elizabeth Dougherty, Harvard-MIT Division of Health Sciences and Technology

Scientists discover record-breaking hydrogen storage materials for use in fuel cells

UVa researchers found materials that absorb hydrogen up to 14 percent by weight at room temperature. By absorbing twice as much hydrogen, the new materials could help make the dream of a hydrogen economy come true.

K.S.Parthasarathy





Public release date: 12-Nov-2007
[ Print Article | E-mail Article | Close Window ]

Contact: Bellave Shivaram
bss2d@virginia.edu
434-806-9582
University of Virginia
Scientists discover record-breaking hydrogen storage materials for use in fuel cells

Scientists at the University of Virginia have discovered a new class of hydrogen storage materials that could make the storage and transportation of energy much more efficient — and affordable — through higher-performing hydrogen fuel cells.

Bellave S. Shivaram and Adam B. Phillips, the U.Va. physicists who invented the new materials, will present their finding at 8 p.m., Monday, Nov. 12, at the International Symposium on Materials Issues in a Hydrogen Economy at the Omni Hotel in Richmond, Va.

“In terms of hydrogen absorption, these materials could prove a world record,” Phillips said. “Most materials today absorb only 7 to 8 percent of hydrogen by weight, and only at cryogenic [extremely low] temperatures. Our materials absorb hydrogen up to 14 percent by weight at room temperature. By absorbing twice as much hydrogen, the new materials could help make the dream of a hydrogen economy come true.”

In the quest for alternative fuels, U.Va.’s new materials potentially could provide a highly affordable solution to energy storage and transportation problems with a wide variety of applications. They absorb a much higher percentage of hydrogen than predecessor materials while exhibiting faster kinetics at room temperature and much lower pressures, and are inexpensive and simple to produce.

“These materials are the next generation in hydrogen fuel storage materials, unlike any others we have seen before,” Shivaram said. “They have passed every litmus test that we have performed, and we believe they have the potential to have a large impact.”

The inventors believe the novel materials will translate to the marketplace and are working with the U.Va. Patent Foundation to patent their discovery.

“The U.Va. Patent Foundation is very excited to be working with a material that one day may be used by millions in everyday life,” said Chris Harris, senior licensing manager for the U.Va. Patent Foundation. “Dr. Phillips and Dr. Shivaram have made an incredible breakthrough in the area of hydrogen absorption.”

###

Phillips’s and Shivaram’s research was supported by the National Science Foundation and the U.S. Department of Energy.

World's smallest radio uses single nanotube to pick up good vibrations

Public release date: 31-Oct-2007
[ Print Article | E-mail Article | Close Window ]

Contact: Robert Sanders
rsanders@berkeley.edu
510-643-6998
University of California - Berkeley
World's smallest radio uses single nanotube to pick up good vibrations

Berkeley -- Physicists at the University of California, Berkeley, have built the smallest radio yet - a single carbon nanotube one ten-thousandth the diameter of a human hair that requires only a battery and earphones to tune in to your favorite station.

The scientists successfully received their first FM broadcast last year - Derek & The Dominos' "Layla" and the Beach Boys' "Good Vibrations" transmitted from across the room. In homage to last year's 100th anniversary of the first voice and music radio transmission, they also transmitted and successfully tuned in to the first music piece broadcast in 1906, "Largo" from George Frederic Handel's opera "Xerxes."

"We were just in ecstasy when this worked," said team leader Alex Zettl, UC Berkeley professor of physics. "It was fantastic."

The nanoradio, which is currently configured as a receiver but could also work as a transmitter, is 100 billion times smaller than the first commercial radios, and could be used in any number of applications - from cell phones to microscopic devices that sense the environment and relay information via radio signals, Zettl said. Because it is extremely energy efficient, it would integrate well with microelectronic circuits.

"The nanotube radio may lead to radical new applications, such as radio-controlled devices small enough to exist in a human's bloodstream," the authors wrote in a paper published online today by the journal Nano Letters. The paper will appear in the print edition of Nano Letters later this month.

Authors of the nanoradio paper are Zettl, graduate student Kenneth Jensen, and their colleagues in UC Berkeley's Center of Integrated Nanomechanical Systems (COINS) and in the Materials Sciences Division at Lawrence Berkeley National Laboratory (LBNL). COINS is a Nanoscale Science and Engineering Research Center supported by the National Science Foundation (NSF).

Nanotubes are rolled-up sheets of interlocked carbon atoms that form a tube so strong that some scientists have suggested using a nanotube wire to tether satellites in a fixed position above Earth. The nanotubes also exhibit unusual electronic properties because of their size, which, for the nanotubes used in the radio receiver, are about 10 nanometers in diameter and several hundred nanometers long. A nanometer is one billionth of a meter; a human hair is about 50,000-100,000 nanometers in diameter.

In the nanoradio, a single carbon nanotube works as an all-in-one antenna, tuner, amplifier and demodulator for both AM and FM. These are separate components in a standard radio. A demodulator removes the AM or FM carrier frequency, which is in the kiloHertz and megaHertz range, respectively, to retrieve the lower frequency broadcast information.

The nanoradio detects radio signals in a radically new way - it vibrates thousands to millions of times per second in tune with the radio wave. This makes it a true nanoelectromechanical device, dubbed NEMS, that integrates the mechanical and electrical properties of nanoscale materials.

In a normal radio, ambient radio waves from different transmitting stations generate small currents at different frequencies in the antenna, while a tuner selects one of these frequencies to amplify. In the nanoradio, the nanotube, as the antenna, detects radio waves mechanically by vibrating at radio frequencies. The nanotube is placed in a vacuum and hooked to a battery, which covers its tip with negatively charged electrons, and the electric field of the radio wave pushes and pulls the tip thousands to millions of times per second.

While large objects, like a stiff wire or a wooden ruler pinned at one end, vibrate at low frequencies - between tens and hundreds of times per second - the tiny nanotubes vibrate at high frequencies ranging from kiloHertz (thousands of times per second) to hundreds of megaHertz (100 million times per second). Thus, a single nanotube naturally selects only one frequency.

Although it might seem that the vibrating nanotube yields a "one station" radio, the tension on the nanotube also influences its natural vibration frequency, just as the tension on a guitar string fine tunes its pitch. As a result, the physicists can tune in a desired frequency or station by "pulling" on the free tip of the nanotube with a positively charged electrode. This electrode also turns the nanotube into an amplifier. The voltage is high enough to pull electrons off the tip of the nanotube and, because the nanotube is simultaneously vibrating, the electron current from the tip is an amplified version of the incoming radio signal. This is similar to the field-emission amplification of old vacuum tube amplifiers used in early radios and televisions, Zettl said. The amplified output of this simple nanotube device is enough to drive a very sensitive earphone.

Finally, the field-emission and vibration together also demodulate the signal.

"I hate to sound like I'm selling a Ginsu knife - But wait, there's more! It also slices and dices! - but this one nanotube does everything; it performs all radio functions simultaneously and extremely efficiently," Zettl said. "It's ridiculously simple - that's the beauty of it."

Zettl's team assembles the nanoradios very simply, too. From nanotubes copiously produced in a carbon arc, they glue several to a fixed electrode. In a vacuum, they bring the electrode within a few microns of a second electrode, close enough for electrons to jump to it from the closest nanotube and create an electrical circuit. To achieve the desired length of the active nanotube, the team first runs a large current through the nanotube to the second electrode, which makes carbon atoms jump off the tip of the nanotube, trimming it down to size for operation within a particular frequency band. Connect a battery and earphones, and voila!

Reception by the initial radios is scratchy, which Zettl attributes in part to insufficient vacuum. In future nanoradios, a better vacuum can be obtained by insuring a cleaner environment, or perhaps by encasing the single nanotube inside a second, larger non-conducting nanotube, thereby retaining the nanoscale.

Zettl won't only be tuning in to oldies stations with his nanoradio. Because the radio static is actually the sound of atoms jumping on and off the tip of the nanotube, he hopes to use the nanoradio to sense the identity of atoms or even measure their masses, which is done today by cumbersome large mass spectrometers.

###

Coauthors with Jensen and Zettl are UC Berkeley post-doctoral fellow Jeff Weldon and physics graduate student Henry Garcia. The work was supported by NSF and the U.S. Department of Energy.