Cancer is a disease whose treatments are notoriously indiscriminate and nonspecific. Researchers have been searching for a highly targeted medical treatment that attacks cancer cells but leaves healthy tissue alone. The approach taken by scientists at Washington University in St. Louis (WUSTL) is to use "gold nanocages" that, when injected, selectively accumulate in tumors. When the tumors are later bathed in laser light, the surrounding tissue is barely warmed, but the nanocages convert light to heat, killing the malignant cells.

The new process nears similarities to one being developed at the University of California in Santa Cruz using hollow gold nanospheres and another in development at Rice University using exploding gold nanoparticles. Gold is an attractive substance for the researchers because it is inert in the body. Gold salts and gold colloids, (a type of mixture in which one substance is dispersed evenly through another), have been used to treat arthritis for over 100 years so it is believed the nanocages themselves will be nontoxic.

The nanocages are hollow boxes made by precipitating gold on silver nanoparticles. The silver simultaneously erodes from within the cube, entering solution through pores that open in the clipped corners of the cube.



To stop proteins depositing on the nanoparticles, which would result in them being captured by the immune system and dragged out of the bloodstream into the liver or spleen, the scientists coated the nanocages with a layer of PEG. PEG is a nontoxic chemical most people have encountered in the form of the laxatives GoLyTELY or MiraLAX. It resists the adsorption of proteins, in effect disguising the nanoparticles so that the immune system cannot recognize them. This allows them to circulate in the bloodstream long enough to accumulate in tumors.

A growing tumor must develop its own blood supply to prevent its core from being starved of oxygen and nutrients. But tumor vessels are as aberrant as tumor cells so they have irregular diameters and abnormal branching patterns, but most importantly, they have thin, leaky walls. The cells that line a tumor's blood vessel, normally packed so tightly they form a waterproof barrier, are disorganized and irregularly shaped, and there are gaps between them. The nanocages infiltrate through those gaps efficiently enough that they turn the surface of the normally pinkish tumor black.

The suspensions of the gold nanocages, which are roughly the same size as a virus particle, are not always yellow. They are colored by something called a surface Plasmon resonance. The resonance – and the color – can be tuned over a wide range of wavelengths by altering the thickness of the cages’ walls. In other words, their color and their ability to absorb light and convert it to heat can be precisely controlled.



For biomedical applications, the WUSTL scientists tune the cages to 800 nanometers, a wavelength that falls in a window of tissue transparency that lies between 750 and 900 nanometers, in the near-infrared part of the spectrum. Light in this sweet spot can penetrate as deep as several inches in the body (either from the skin or the interior of the gastrointestinal tract or other organ systems).

The conversion of light to heat arises from the same physical effect as the color. The resonance has two parts. At the resonant frequency, light is typically both scattered off the cages and absorbed by them. Controlling the cages' size tailors them to achieve maximum absorption.


[gizmag]

Diabetes has transformed into a fatal disease all around the world. While doctors are making all possible attempts to diagnose patients as early as possible, labs and research institutes are developing ways to make life normal and less painful for the suffering. Different types of blood glucose level measuring devices and insulin injecting gadgets have made to the fore, adding to tally a little differently is the Glucowizzard from Biorasis. It is a rice grain-sized solar powered implantable sensor, which hides underneath the skin for about a year at a stretch and measures the blood glucose levels consistently all the while.


This is a great introduction to rid patients of the frequent pricks they have to undergo daily to keep a check on the blood glucose levels. The sensor, almost like the glucose monitors we’ve seen, in functionality, send data to a variety of portable electronic devices such as cellphones and PDAs, alerting the patient each time the blood sugar levels go high. Clinical trials of the device are expected to being in two years, while the sensor could go on sale by 2017.





[gizmowatch]

Rate of MRI and CT/PET scans ordered or provided have tripled from 1996 to 2007

A boom in medical technology over the past decade or two has led to a surge in certain medical tests and increased prescription drug use, say authors of a report that provides a snapshot of Americans’ health today.Imaging, assisted reproductive technologies, prescription drugs and knee replacements have all seen a dramatic rise since the early ’90s, says Amy Bernstein, the report’s lead author, a health scientist for the National Center for Health Statistics. The center, part of the Centers for Disease Control and Prevention, released the 33rd annual Report on the Nation’s Health Wednesday. It includes a special section on health technology.

“There are newer and better technologies all the time, and they’re changing the face of health care and practice patterns,” Bernstein says.

She points to report findings that show the use of statin drugs, which lower cholesterol, increased almost tenfold from 1994 to 2006 in adults over age 45.

“One of the reasons cholesterol is declining and people are living longer with heart disease is because we have better drugs. Technologies can be very helpful,” she says.

Other indications from the report of how medical technology has heavily influenced medical treatments Americans receive:

• Imaging: Rate of MRI (magnetic resonance imaging) and CT/PET (computed tomography/positron emission tomography) scans ordered or provided in doctors offices and emergency departments tripled from 1996 to 2007.

• Knee replacement: Rate of adults 45 and over discharged from the hospital after receiving at least one knee replacement increased 70% from 1996 to 2006 (26.5 per 10,000 in 1996 vs. 45.2 per 10,000 in 2006).

• Diabetes medicines: Anti-diabetic drug use by people 45 and up increased about 55% when comparing 1988-1994 with 2003-2006 figures.

• Kidney transplants: New kidney transplants per 1 million people have risen 31% (43.7 per 1 million in 1997 vs. 57.2 in 2006).

• Liver transplants: They rose 42% from 1997 to 2006 (15.6 per 1 million in 1997 vs. 22.2 in 2006).

• Prescription drugs: The percentage of the population taking at least one prescription drug during the previous month increased from 38% in 1988-1994 to 47% in 2003-2006, and the percentage taking three or more prescription drugs increased from 11% to 21%.

In general, the report sends a positive message, says Phil Hagen, vice chair of the division of preventive medicine at Mayo Clinic. “We’re winning the battle in some diseases, particularly cardiovascular disease.”

There’s still room for improvement, says Lloyd Michener, director of the Duke Center for Community Research. “The report helps us rethink where we’re headed,” he says. “It’s a call for accelerated efforts that will build partnerships between academic medical centers and public health groups in order to address some of our persistent health issues.”


[impactlab]

A couple of days late for Valentine's Day but just in time for Mardi Gras, we find out biotechnology scientists have discovered a compound that functions like a female version of the male libido-enhancing drug Viagra.

Called Flibanserin, this alleged female aphrodisiac was originally developed as an antidepressant. Like most antidepressants, the drug's efficacy was questionable. Strangely enough, after 24 weeks of popping the pills, women found themselves a whole lot hornier than they were when they started treatment, enjoying "an increase in satisfactory sexual encounters."

Don't expect to be using these superchargers right away, though, because they haven't been thoroughly tested yet. However, scientists are saying the stuff shows promise. How does it work? It alters serotonin levels in that most important sex organ of all, the brain.




About Flibanserin

Flibanserin (BIMT-17) is a drug produced by Boehringer Ingelheim.^[1] It is currently being investigated as a drug for women with decreased sexual desire.^[2] It is a 5-HT_1A serotonin receptor agonist, a 5-HT_2A serotonin receptor antagonist, and a dopamine D4 receptor partial agonist that had initially been developed as an anti-depressant.^[3][4] As with Viagra, the effects of flibanserin were discovered serendipitously after it was trialled as an antidepressant.


^{[scientificameria]}