The new house call: Your doctor's at the door, er, on your Web cam
Too busy to go to the doctor? Unfortunately, it's the rare one who makes house calls these days. But how about the next best thing? The Hawaii Medical Service Association (HMSA) next week is set to begin offering doctor consults via Web cam, an emerging form of telemedicine.
The association (the state's Blue Cross Blue Shield insurance provider) will offer the 10-minute Internet visits through American Well, a Boston-based company that provides video conferencing and electronic medical record-keeping to doctors and patients, the New York Times reports today. HMSA is its first customer, the Times says. “It’s a better iteration on, ‘Take two aspirin and call me in the morning,’” Robert Sussman, a family practice doctor on Oahu, tells the newspaper. “We can’t lay on the hands, but we can lay on the eyes and get a better feel" than from a simple phone consult.
Telemedicine – by Internet or phone – is touted as a convenience for folks who don’t want to wait days for a doctor’s appointment, who don’t live near a physician, and who are willing to pay out of pocket for the perk of a visit on their own schedule. The cost is a $10 co-pay for HMSA members and $45 for non-members. Proponents say doctors can take care of about half of medical problems without a face-to-face workup.
While some traditional doctors consult with regular patients by phone or email, many don’t, says Jay Parkinson, a primary-care doctor who runs the telemedicine business Hello Health in Brooklyn, N.Y. “Doctors don’t get paid for communications – only office visits and procedures,” Parkinson tells ScientificAmerican.com. “Nowadays doctors see so many patients – 30, 40, 50 patients a day. When the day is over, they can’t sit down and answer 50 emails for free.”
Hello Health's fees are based on the length and type of visit: $100-to-$200 for an office visit versus $50-to-$100 for video, instant message and phone visits. (If the latter leads to an office visit or house call, that charge is applied to the cost of the in-person exam.) A similar service, Doctokr in Vienna, Va., a suburb of Washington, D.C., also provides scaled fees for phone, office and house consults. Both businesses require patients to be seen at least once in person.
Internet-based medicine is still in its infancy, Parkinson says, and whether it’s ideally practiced via Web cam or by text-based instant messaging or email is an open question. Just 16 percent of Internet users have used a Web cam, according to a 2005 report by the Pew Internet & American Life Project.
Whatever its form, telemedicine is really best suited for relatively minor problems, Parkinson says, and to determine whether further medical attention or lab tests are needed to check out, say, swollen lymph nodes or whether a sore throat may be strep. “We target someone who communicates and transacts online, and that’s everyone under 65 these days,” he says. But, a doctor really needs "to have a [previous] relationship with someone. Otherwise, it’s sort of reckless.”
Source>Scientific American
วันศุกร์ที่ 5 มิถุนายน พ.ศ. 2552
Who Needs a Doctor
When There's a Robot in the House, er, Hospital? [Slide Show]A Florida trauma center tests the use of a mobile robot to deliver telemedicine
By Larry Greenemeier
Scientificamerican:December 4, 2008
Telemedicine has caught on over the past several years as an effective way to bring patients and specialists together via the magic of video conferencing. Unfortunately, most telemedicine setups require the patient to be in a room equipped with a computer, camera, microphone and monitor, so that specialists can remotely assess his or her condition. Could robots be the answer, providing both patient care and a view for specialists checking in from afar?
The William Lehman Injury Research Center (WLIRC) in Miami for a year has been experimenting with a budding type of telemedicine that uses a robot to let videoconferencing go mobile, allowing a specialist working from a remote location to see a patient (and for the patient to see the physician) from the moment he or she checks in for surgery through recovery.
A typical scenario would unfold as such: A patient is brought to the Ryder Trauma Center at the University of Miami's Jackson Memorial Hospital (where the WLIRC doctors work) by ambulance or helicopter. While the patient is en route, the trauma center checks to see if there is a specialist on site who can treat the patient's specific injuries. If there are none available and the specialist on call is unable to make it to Ryder in time, staff at the center wheel out the RP-7, made by InTouch Technologies, Inc., a Santa Barbara, Calif., medical robotics technology company. Once a specialist is located, he or she uses a laptop or PC to remotely connect via wireless broadband with the robot. After the connection is made, the specialist is able to control the robot's movement, possibly even meeting the patient at the door. From there, the specialist can autonomously drive the robot to operating rooms, intensive care units and patients' bedsides so he or she can monitor those patients as well as instruct nurses and residents.
View a slideshow of the RP-7 in action
The WLIRC doctors and physicians from the U.S. Army's Trauma Training Center (working at the Ryder Trauma Center) have been testing the RP-7, to see if the above scenario is realistic. The 200-pound, (90.7-kilogram) 67-inch- (1.7-meter-) tall metal medical man glides along on three spherical balls (rather than wheels) at a top speed of four miles (6.4 kilometers) per hour. As the Army's Web site points out, it "looks vaguely like one of the Daleks [robots] from Doctor Who with a view screen mounted on top."
Ryder is the only "level 1" trauma center in Miami–Dade County, which makes it difficult to find specialists to weigh in on all cases, particularly within the critical first 60 minutes after an injury, says Jeffrey Augenstein, WLIRC's director and the RP-7 project's principal investigator. "There is a shortage of trauma specialists in this country," he says. "You need to have a plan B to bring expertise from the outside to the point of care, where decisions often involve life and death."
Source>http://www.scientificamerican.com/article.cfm?id=robot-telemedicine
By Larry Greenemeier
Scientificamerican:December 4, 2008
Telemedicine has caught on over the past several years as an effective way to bring patients and specialists together via the magic of video conferencing. Unfortunately, most telemedicine setups require the patient to be in a room equipped with a computer, camera, microphone and monitor, so that specialists can remotely assess his or her condition. Could robots be the answer, providing both patient care and a view for specialists checking in from afar?
The William Lehman Injury Research Center (WLIRC) in Miami for a year has been experimenting with a budding type of telemedicine that uses a robot to let videoconferencing go mobile, allowing a specialist working from a remote location to see a patient (and for the patient to see the physician) from the moment he or she checks in for surgery through recovery.
A typical scenario would unfold as such: A patient is brought to the Ryder Trauma Center at the University of Miami's Jackson Memorial Hospital (where the WLIRC doctors work) by ambulance or helicopter. While the patient is en route, the trauma center checks to see if there is a specialist on site who can treat the patient's specific injuries. If there are none available and the specialist on call is unable to make it to Ryder in time, staff at the center wheel out the RP-7, made by InTouch Technologies, Inc., a Santa Barbara, Calif., medical robotics technology company. Once a specialist is located, he or she uses a laptop or PC to remotely connect via wireless broadband with the robot. After the connection is made, the specialist is able to control the robot's movement, possibly even meeting the patient at the door. From there, the specialist can autonomously drive the robot to operating rooms, intensive care units and patients' bedsides so he or she can monitor those patients as well as instruct nurses and residents.
View a slideshow of the RP-7 in action
The WLIRC doctors and physicians from the U.S. Army's Trauma Training Center (working at the Ryder Trauma Center) have been testing the RP-7, to see if the above scenario is realistic. The 200-pound, (90.7-kilogram) 67-inch- (1.7-meter-) tall metal medical man glides along on three spherical balls (rather than wheels) at a top speed of four miles (6.4 kilometers) per hour. As the Army's Web site points out, it "looks vaguely like one of the Daleks [robots] from Doctor Who with a view screen mounted on top."
Ryder is the only "level 1" trauma center in Miami–Dade County, which makes it difficult to find specialists to weigh in on all cases, particularly within the critical first 60 minutes after an injury, says Jeffrey Augenstein, WLIRC's director and the RP-7 project's principal investigator. "There is a shortage of trauma specialists in this country," he says. "You need to have a plan B to bring expertise from the outside to the point of care, where decisions often involve life and death."
Source>http://www.scientificamerican.com/article.cfm?id=robot-telemedicine
Brain Rerouting signal
Skip the Robotics: Paralyzed Limbs Come to Life
with New Connection to Brain
Rerouting signal from neuron to muscle allows the brain to move deadened limbs
By Sharon Guynup
From the February 2009
Scientific American
Scientists have forged a promising avenue in the quest to restore mobility to patients paralyzed by disease or injury. Researchers at the University of Washington devised a way to reroute signals from the brain’s motor cortex to trigger hand movement directly.
For the past decade researchers have focused on “listening to” and decoding the specific brain signals that trigger muscle movement, using a wall of computers running complex algorithms to translate that brain activity into instructions for moving a computer cursor or a robotic arm or leg.
The new approach simplifies the process. Engineers and neuroscientists restored use of a monkey’s immobilized limb by replacing the lost biological connection. “Rather than decoding intention, we’ve just established a connection and encouraged the monkey to learn how to act on it,” says Chet Moritz, a neurophysiologist, who pioneered the work with fellow Washington professor Eberhard Fetz.
They trained macaques to play a simple video game using a joystick. Then they ran a wire from a single neuron in the animals’ motor cortex to a desktop computer. The electrical impulse from that cell was amplified by the computer and transmitted along another wire to one of the primates’ arm muscles, which had been temporarily anesthetized.
Within minutes, the monkeys learned to control wrist movements with their thoughts, moving the joystick left or right to match targets on a computer screen.
The surprise, Moritz says, was that any neuron within that general region of the brain could learn to stimulate wrist muscles—regardless of whether the neuron was originally involved in that specific movement.
“Monkeys can rapidly learn to change neuron activity, in this case to generate movement, much like humans can change heart rate activity with biofeedback,” Fetz explains. This control necessitated conscious attention; making such movements subconsciously would require repetitive training, much like learning a sport.
The long-term goal is to develop a miniaturized, implantable neuroprosthetic device that would enable paralyzed patients to move their own paralyzed limbs. Fetz has already taken the next step, developing a cell phone–size neurochip that can be linked to a microprocessor, small enough for monkeys to carry implanted in their head.
Many hurdles remain. It is difficult to record from the same neuron for a long period. Within days or weeks, scar tissue walls off electrodes, interrupting transmission. Guiding electrodes to new locations with tiny motors might mitigate that problem. Providing a decades-long power supply is also a challenge. Biocompatibility is another issue; fully implanting such a system under the skin presents a huge infection risk. And crucial questions exist: Can this model be scaled up to stimulate multiple neurons that trigger multiple muscles? How flexible is the brain in reassigning new functions to neurons?
The team hopes to restore arm movements in the near term—and ultimately to restore paraplegics’ ability to walk. But clinical trials remain perhaps a decade away.
Source>http://www.scientificamerican.com/article.cfm?id=robotics-provide-hope
with New Connection to Brain
Rerouting signal from neuron to muscle allows the brain to move deadened limbs
By Sharon Guynup
From the February 2009
Scientific American
Scientists have forged a promising avenue in the quest to restore mobility to patients paralyzed by disease or injury. Researchers at the University of Washington devised a way to reroute signals from the brain’s motor cortex to trigger hand movement directly.
For the past decade researchers have focused on “listening to” and decoding the specific brain signals that trigger muscle movement, using a wall of computers running complex algorithms to translate that brain activity into instructions for moving a computer cursor or a robotic arm or leg.
The new approach simplifies the process. Engineers and neuroscientists restored use of a monkey’s immobilized limb by replacing the lost biological connection. “Rather than decoding intention, we’ve just established a connection and encouraged the monkey to learn how to act on it,” says Chet Moritz, a neurophysiologist, who pioneered the work with fellow Washington professor Eberhard Fetz.
They trained macaques to play a simple video game using a joystick. Then they ran a wire from a single neuron in the animals’ motor cortex to a desktop computer. The electrical impulse from that cell was amplified by the computer and transmitted along another wire to one of the primates’ arm muscles, which had been temporarily anesthetized.
Within minutes, the monkeys learned to control wrist movements with their thoughts, moving the joystick left or right to match targets on a computer screen.
The surprise, Moritz says, was that any neuron within that general region of the brain could learn to stimulate wrist muscles—regardless of whether the neuron was originally involved in that specific movement.
“Monkeys can rapidly learn to change neuron activity, in this case to generate movement, much like humans can change heart rate activity with biofeedback,” Fetz explains. This control necessitated conscious attention; making such movements subconsciously would require repetitive training, much like learning a sport.
The long-term goal is to develop a miniaturized, implantable neuroprosthetic device that would enable paralyzed patients to move their own paralyzed limbs. Fetz has already taken the next step, developing a cell phone–size neurochip that can be linked to a microprocessor, small enough for monkeys to carry implanted in their head.
Many hurdles remain. It is difficult to record from the same neuron for a long period. Within days or weeks, scar tissue walls off electrodes, interrupting transmission. Guiding electrodes to new locations with tiny motors might mitigate that problem. Providing a decades-long power supply is also a challenge. Biocompatibility is another issue; fully implanting such a system under the skin presents a huge infection risk. And crucial questions exist: Can this model be scaled up to stimulate multiple neurons that trigger multiple muscles? How flexible is the brain in reassigning new functions to neurons?
The team hopes to restore arm movements in the near term—and ultimately to restore paraplegics’ ability to walk. But clinical trials remain perhaps a decade away.
Source>http://www.scientificamerican.com/article.cfm?id=robotics-provide-hope
artificial Heart valve
April 25, 2009
Artificial Valves That Lend Hearts a Helping Hand
For the past five decades, artificial heart-valve designs have evolved to successfully replace natural valves, which often begin to leak or harden over time
By Amber Dance
The heart relies on four valves that act as one-way gates, controlling blood flow out of each of the heart's four chambers. The mitral valve between the two left chambers of the heart has two leaflets, or cusps; the tricuspid, pulmonary and aortic valves each have three. The leaflets swing open and shut like saloon doors with every beat, maintaining a steady blood supply. (A person's heart generally beats 80 million times a year and five to six billion times over the course of a normal lifetime, according to Irvine, Calif.–based valve producer Edwards Lifesciences.)
> Slide Show: Artificial heart valve improvements over the past 50 years
As comedian and actor Robin Williams, 57, and 83-year-old former first lady Barbara Bush found out recently, in many cases, the valves don't last a lifetime; some become leaky. Called a regurgitating valve, this allows pumped blood to wash back into the heart. Others pick up calcium from the blood, eventually becoming hardened, restricting blood flow (a condition known as stenosis). When the body does not receive enough blood, a person can experience symptoms such as shortness of breath. Aortic and mitral valves most commonly require treatment. Once symptoms such as lightheadedness and blackouts arise, a person with an untreated faulty aortic valve has a 50 percent chance of dying within six months, says Eugene Grossi, a professor of cardiothoracic surgery at New York University School of Medicine and director of cardiac surgery research.That means that for thousands of Americans, an artificial heart valve fashioned from tissue-thin flaps is all that stands between health and heart failure. About 140,000 Americans go under the knife for valve replacement or repair every year, according to Toronto-based Millennium Research Group, a firm that tracks the medical device, pharmaceutical and biotechnology industries.Doctors have developed several stand-ins for the natural tissue that can regulate blood flow without missing a beat. "Heart valves are the one device that when you get it in and it's successful, you add 10 or 15 years to their life," says Donald Bobo, vice president for heart valve therapy at Edwards Lifesciences. Edwards—along with Saint Jude Medical in Saint Paul, Minn., and Minneapolis-based Medtronic, Inc.—is a top provider of artificial valves worldwide, Bobo says. Sorin Group in Milan, Italy, also has a share in the global heart valve therapy market, estimated to be worth $1.6 billion in 2008, according to Edwards market estimates.Valve technology took off in 1958 when engineer and Edwards founder Miles "Lowell" Edwards applied his experience designing hydraulic debarking methods for the lumber industry and a fuel-injection system for World War II aircraft to the medical arena. Working with cardiothoracic surgeon Albert Starr, the two developed a valve that Starr could use in his ailing patients. Surgeons implanted the Starr-Edwards artificial valve, designed in Edward's backyard workshop, for the first time in 1960. Although that first patient died shortly after receiving the device, the second survived for 10 more years before dying from a fall off a ladder.People tried dozens of different designs in the ensuing decades, says Ajit Yoganathan, a biomedical engineer who studies valves at the Georgia Institute of Technology in Atlanta. "Most of them were developed in someone's garage or someone's basement." The technology has evolved from a caged-ball design into valves with artificial flaps, pig valves processed for human use, and hand-sewn biologic valves made from cow tissue."All of these valves have analogues in hydraulics, pipelines, aviation, automobiles," Bobo says. But the human body presents special challenges. "Blood ends up being a pretty different environment compared to oil or gas," he adds. The lipids in blood can destroy synthetic materials; tissue valves are subject to the same wear and tear and calcification that natural valves are."There is still room for improvement," such as better materials, Yoganathan says. He would also like to see small valves available to children with congenital heart defects. The next development likely to hit the U.S. market is valves that can be implanted without open heart surgery.
Source:>http://www.scientificamerican.com/article.cfm?id=artificial-heart-valves
Artificial Valves That Lend Hearts a Helping Hand
For the past five decades, artificial heart-valve designs have evolved to successfully replace natural valves, which often begin to leak or harden over time
By Amber Dance
The heart relies on four valves that act as one-way gates, controlling blood flow out of each of the heart's four chambers. The mitral valve between the two left chambers of the heart has two leaflets, or cusps; the tricuspid, pulmonary and aortic valves each have three. The leaflets swing open and shut like saloon doors with every beat, maintaining a steady blood supply. (A person's heart generally beats 80 million times a year and five to six billion times over the course of a normal lifetime, according to Irvine, Calif.–based valve producer Edwards Lifesciences.)
> Slide Show: Artificial heart valve improvements over the past 50 years
As comedian and actor Robin Williams, 57, and 83-year-old former first lady Barbara Bush found out recently, in many cases, the valves don't last a lifetime; some become leaky. Called a regurgitating valve, this allows pumped blood to wash back into the heart. Others pick up calcium from the blood, eventually becoming hardened, restricting blood flow (a condition known as stenosis). When the body does not receive enough blood, a person can experience symptoms such as shortness of breath. Aortic and mitral valves most commonly require treatment. Once symptoms such as lightheadedness and blackouts arise, a person with an untreated faulty aortic valve has a 50 percent chance of dying within six months, says Eugene Grossi, a professor of cardiothoracic surgery at New York University School of Medicine and director of cardiac surgery research.That means that for thousands of Americans, an artificial heart valve fashioned from tissue-thin flaps is all that stands between health and heart failure. About 140,000 Americans go under the knife for valve replacement or repair every year, according to Toronto-based Millennium Research Group, a firm that tracks the medical device, pharmaceutical and biotechnology industries.Doctors have developed several stand-ins for the natural tissue that can regulate blood flow without missing a beat. "Heart valves are the one device that when you get it in and it's successful, you add 10 or 15 years to their life," says Donald Bobo, vice president for heart valve therapy at Edwards Lifesciences. Edwards—along with Saint Jude Medical in Saint Paul, Minn., and Minneapolis-based Medtronic, Inc.—is a top provider of artificial valves worldwide, Bobo says. Sorin Group in Milan, Italy, also has a share in the global heart valve therapy market, estimated to be worth $1.6 billion in 2008, according to Edwards market estimates.Valve technology took off in 1958 when engineer and Edwards founder Miles "Lowell" Edwards applied his experience designing hydraulic debarking methods for the lumber industry and a fuel-injection system for World War II aircraft to the medical arena. Working with cardiothoracic surgeon Albert Starr, the two developed a valve that Starr could use in his ailing patients. Surgeons implanted the Starr-Edwards artificial valve, designed in Edward's backyard workshop, for the first time in 1960. Although that first patient died shortly after receiving the device, the second survived for 10 more years before dying from a fall off a ladder.People tried dozens of different designs in the ensuing decades, says Ajit Yoganathan, a biomedical engineer who studies valves at the Georgia Institute of Technology in Atlanta. "Most of them were developed in someone's garage or someone's basement." The technology has evolved from a caged-ball design into valves with artificial flaps, pig valves processed for human use, and hand-sewn biologic valves made from cow tissue."All of these valves have analogues in hydraulics, pipelines, aviation, automobiles," Bobo says. But the human body presents special challenges. "Blood ends up being a pretty different environment compared to oil or gas," he adds. The lipids in blood can destroy synthetic materials; tissue valves are subject to the same wear and tear and calcification that natural valves are."There is still room for improvement," such as better materials, Yoganathan says. He would also like to see small valves available to children with congenital heart defects. The next development likely to hit the U.S. market is valves that can be implanted without open heart surgery.
Source:>http://www.scientificamerican.com/article.cfm?id=artificial-heart-valves
Nanoparticles Home in on Brain Cancer
Nanoparticles Home in on Brain Cancer
By Nikhil Swaminathan
November 17, 2006
Call them laser-guided smart bombs for brain tumors. Researchers at the University of Michigan announced the testing of a drug delivery system that involves drug-toting nanoparticles and a guiding peptide to target cancerous cells in the brain. Their study finds that via this method more of the drug can be delivered to a tumor's general vicinity. They report their findings in the November 15 issue of Clinical Cancer Research.
The researchers used a pharmaceutical called Photofrin, which is photodynamic, meaning it is activated by a laser after it has entered the bloodstream. As its primary side effect, the drug renders patients photosensitive, and they must remain out of bright sunlight and even unshaded lamps for up to 30 days after receiving treatment. Despite this major drawback, Photofrin is used in the treatment of esophageal, bladder and skin cancers. But their novel delivery system, which relies on the intravenous delivery of 40-nanometer-wide particles to carry the drug, may actually avoid much of the photosensitivity, because less Photofrin circulates in the bloodstream thanks to a peptide called F3. A sequence of 31 amino acids broken off of the protein HMGN2 (high mobility group protein 2), F3 has the ability to penetrate cell membranes. "This peptide acts as a "zip code" in that it enables the binding of the nanoparticles only to blood vessels within the tumor and not normal blood vessels," says Alnawaz Rehemtulla, a radiologist and environmental health scientist who co-authored the study. F3 can detect the expression of a protein called nucleolin, which is a marker on the surface of tumor cells.
Another problem the researchers avoided was having to deliver their medicine in such a way that it could cross the blood-brain barrier, which keeps many substances from entering the brain from the bloodstream. Typical chemotherapies must penetrate this shield to treat tumors. In this case, however, the nontoxic polyacrylamide particles didn't have to cross over via the bloodstream. "The nanoparticles do not need to cross the blood-brain barrier as they were specifically designed to target the blood vessel cells within the tumor," explains radiologist Brian Ross, one of the study's authors. "The treatment should be thought of as an antivascular treatment thereby shutting off the tumor blood flow resulting in the death of the tumor cells through starvation of oxygen and energy sources."
To test the delivery method, researchers divided 34 rats--all who received injections of cancerous cells into their brains--into different groups. Those that received no treatment or got only the laser fared poorly, dying on average within 8.5 days. Those that got Photofrin either intravenously or encapsulated in nanoparticles had a median survival time of 13 days. The group that got F3 with the Photofrin-carrying nanoparticles came through the best: they lived for, on average, 33 days; three of the five in this grouping lived for 60 days, and two of those three appeared tumor-free after six months. By using iron oxide as a contrast agent--to more easily detect where the nanoparticles ended up via MRI--the group determined that twice as much drug with the F3 peptide attached reached the tumor site--10 percent of the total amount administered--compared with when nontargeted nanoparticles were injected.
Ross says that based on the success of the study, the team is investigating if this delivery technology will work for nonphotodynamic therapies. Rehemtulla adds that if other FDA-approved chemotherapeutic agents reach their targets as successfully as Photofrin did, "then we will have developed a way to make cancer drugs more 'tumor-specific,' because they will only get into tumor vasculature and not normal vasculature. This will spare patients from normal tissue toxicity that is commonly associated with almost all chemotherapy."
Source>http://www.scientificamerican.com/article.cfm?id=nanoparticles-home-in-on
By Nikhil Swaminathan
November 17, 2006
Call them laser-guided smart bombs for brain tumors. Researchers at the University of Michigan announced the testing of a drug delivery system that involves drug-toting nanoparticles and a guiding peptide to target cancerous cells in the brain. Their study finds that via this method more of the drug can be delivered to a tumor's general vicinity. They report their findings in the November 15 issue of Clinical Cancer Research.
The researchers used a pharmaceutical called Photofrin, which is photodynamic, meaning it is activated by a laser after it has entered the bloodstream. As its primary side effect, the drug renders patients photosensitive, and they must remain out of bright sunlight and even unshaded lamps for up to 30 days after receiving treatment. Despite this major drawback, Photofrin is used in the treatment of esophageal, bladder and skin cancers. But their novel delivery system, which relies on the intravenous delivery of 40-nanometer-wide particles to carry the drug, may actually avoid much of the photosensitivity, because less Photofrin circulates in the bloodstream thanks to a peptide called F3. A sequence of 31 amino acids broken off of the protein HMGN2 (high mobility group protein 2), F3 has the ability to penetrate cell membranes. "This peptide acts as a "zip code" in that it enables the binding of the nanoparticles only to blood vessels within the tumor and not normal blood vessels," says Alnawaz Rehemtulla, a radiologist and environmental health scientist who co-authored the study. F3 can detect the expression of a protein called nucleolin, which is a marker on the surface of tumor cells.
Another problem the researchers avoided was having to deliver their medicine in such a way that it could cross the blood-brain barrier, which keeps many substances from entering the brain from the bloodstream. Typical chemotherapies must penetrate this shield to treat tumors. In this case, however, the nontoxic polyacrylamide particles didn't have to cross over via the bloodstream. "The nanoparticles do not need to cross the blood-brain barrier as they were specifically designed to target the blood vessel cells within the tumor," explains radiologist Brian Ross, one of the study's authors. "The treatment should be thought of as an antivascular treatment thereby shutting off the tumor blood flow resulting in the death of the tumor cells through starvation of oxygen and energy sources."
To test the delivery method, researchers divided 34 rats--all who received injections of cancerous cells into their brains--into different groups. Those that received no treatment or got only the laser fared poorly, dying on average within 8.5 days. Those that got Photofrin either intravenously or encapsulated in nanoparticles had a median survival time of 13 days. The group that got F3 with the Photofrin-carrying nanoparticles came through the best: they lived for, on average, 33 days; three of the five in this grouping lived for 60 days, and two of those three appeared tumor-free after six months. By using iron oxide as a contrast agent--to more easily detect where the nanoparticles ended up via MRI--the group determined that twice as much drug with the F3 peptide attached reached the tumor site--10 percent of the total amount administered--compared with when nontargeted nanoparticles were injected.
Ross says that based on the success of the study, the team is investigating if this delivery technology will work for nonphotodynamic therapies. Rehemtulla adds that if other FDA-approved chemotherapeutic agents reach their targets as successfully as Photofrin did, "then we will have developed a way to make cancer drugs more 'tumor-specific,' because they will only get into tumor vasculature and not normal vasculature. This will spare patients from normal tissue toxicity that is commonly associated with almost all chemotherapy."
Source>http://www.scientificamerican.com/article.cfm?id=nanoparticles-home-in-on
Nanocontainers Deliver Drugs
Nanocontainers Deliver Drugs Directly to Cells
By Sarah Graham
April 28, 2003
One challenge to effective drug treatment is getting the medication to exactly the right place. To that end, researchers have been investigating myriad new methods to deliver pharmaceuticals. Findings published in the current issue of the journal Science indicate that tiny nanocontainers composed of polymers may one day distribute drugs to specific spots within individual cells.
Radoslav Savic and his colleagues at McGill University tested the properties of tiny units built out of two types of polymers. The two compounds self-assemble into a spherical shape known as a micelle. One compound, which is hydrophobic (water fearing), aligns facing inwards and the other, which is hydrophilic (water loving), faces outwards. Drugs can then be loaded inside the tiny molecular globs, which measure 20 to 45 nanometers in diameter. The researchers used fluorescent labeling to track the micelles' journeys (see image). They found that the tiny containers could pass through the wall of a rat cell, but did not enter the cell's nucleus. The micelles did, however, penetrate some cell parts, such as mitochondria and the Golgi apparatus, which are important targets for drug delivery.
The scientists also determined that the micelles are very efficient at delivering their hydrophobic drug cargo once inside a cell. This property could mean that doctors may one day be able to administer smaller doses of toxic medications. "These micelles may thus be worth exploring for their potential to selectively deliver drugs to specified subcellular targets," the authors note. In an accompanying commentary, Jeffrey A. Hubbell of the University of Zurich cautions that much work remains to be done, "yet, multifunctional polymer micelles have already come a long way to reaching these ends."
Source >http://www.scientificamerican.com/article.cfm?id=nanocontainers-deliver-dr
By Sarah Graham
April 28, 2003
One challenge to effective drug treatment is getting the medication to exactly the right place. To that end, researchers have been investigating myriad new methods to deliver pharmaceuticals. Findings published in the current issue of the journal Science indicate that tiny nanocontainers composed of polymers may one day distribute drugs to specific spots within individual cells.
Radoslav Savic and his colleagues at McGill University tested the properties of tiny units built out of two types of polymers. The two compounds self-assemble into a spherical shape known as a micelle. One compound, which is hydrophobic (water fearing), aligns facing inwards and the other, which is hydrophilic (water loving), faces outwards. Drugs can then be loaded inside the tiny molecular globs, which measure 20 to 45 nanometers in diameter. The researchers used fluorescent labeling to track the micelles' journeys (see image). They found that the tiny containers could pass through the wall of a rat cell, but did not enter the cell's nucleus. The micelles did, however, penetrate some cell parts, such as mitochondria and the Golgi apparatus, which are important targets for drug delivery.
The scientists also determined that the micelles are very efficient at delivering their hydrophobic drug cargo once inside a cell. This property could mean that doctors may one day be able to administer smaller doses of toxic medications. "These micelles may thus be worth exploring for their potential to selectively deliver drugs to specified subcellular targets," the authors note. In an accompanying commentary, Jeffrey A. Hubbell of the University of Zurich cautions that much work remains to be done, "yet, multifunctional polymer micelles have already come a long way to reaching these ends."
Source >http://www.scientificamerican.com/article.cfm?id=nanocontainers-deliver-dr
New Drug Delivery
New Drug Delivery Technique Avoids NeedlesBy Sarah Graham
Hypodermic needles are the stuff of nightmares for many people, but they represent a common method for administering a variety of drugs. Patients who fear a needle prick, however, may soon have an alternative, painless way to receive medication. A new technique described today in the journal BMC Medicine uses a stream of gas to help deliver drugs through the skin with what subjects describe as the sensation of a gentle stream of air.
James Weaver of the Massachusetts Institute of Technology and his colleagues developed the novel procedure, which is known as microscission. It uses minuscule inert crystals of aluminum oxide to remove the rough outer layer of skin and create tiny holes, known as microconduits and measuring less than a quarter of a millimeter in diameter, through which medication can move. A jet of flowing gas then takes the crystals and the loosened skin away. After creating four microconduits on the inner arm of volunteers, the team applied a pad soaked in the anesthetic lidocaine. Within two minutes, the drug had worked and the subjects reported no feeling in the region.
The size and depth of the microconduits is determined by holes punched in a polymer mask laid on top of the skin. The team reports that "the onset of anesthesia takes longer in microconduits deep enough to yield blood than in shallower, nonblood producing microconduits." But deep microconduits do have some advantages. Patients suffering from diabetes, for example, often have to jab a finger to test their blood sugar; microscission could represent a less painful alternative, the team suggests.
Source>http://www.scientificamerican.com
Hypodermic needles are the stuff of nightmares for many people, but they represent a common method for administering a variety of drugs. Patients who fear a needle prick, however, may soon have an alternative, painless way to receive medication. A new technique described today in the journal BMC Medicine uses a stream of gas to help deliver drugs through the skin with what subjects describe as the sensation of a gentle stream of air.
James Weaver of the Massachusetts Institute of Technology and his colleagues developed the novel procedure, which is known as microscission. It uses minuscule inert crystals of aluminum oxide to remove the rough outer layer of skin and create tiny holes, known as microconduits and measuring less than a quarter of a millimeter in diameter, through which medication can move. A jet of flowing gas then takes the crystals and the loosened skin away. After creating four microconduits on the inner arm of volunteers, the team applied a pad soaked in the anesthetic lidocaine. Within two minutes, the drug had worked and the subjects reported no feeling in the region.
The size and depth of the microconduits is determined by holes punched in a polymer mask laid on top of the skin. The team reports that "the onset of anesthesia takes longer in microconduits deep enough to yield blood than in shallower, nonblood producing microconduits." But deep microconduits do have some advantages. Patients suffering from diabetes, for example, often have to jab a finger to test their blood sugar; microscission could represent a less painful alternative, the team suggests.
Source>http://www.scientificamerican.com
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