August 2012 – GOLLYGEE!

08.31.2012

cyborg skin

Some Harvard & MIT scientists have developed a 3-D material that can act as a scaffold for human tissues. This material will allow tissues to grow and be able to monitor and report on the tissue’s health. Scientists are hoping it will help in development of new prosthetic devices. From PopSci:

[S]cientists led by MIT professor Robert Langer and Harvard chemistry professor Charles Lieber set out to build a 3-D scaffold that more closely resembles real tissue. The team wanted to build sensors that would let them monitor how the tissue responds to drugs in real time.

The scaffold is made from epoxy embedded with silicon nanowires, which can carry electrical signals to and from the cells. The mesh was folded or rolled into a structure resembling either tissue or vasculature. The nanowires can detect voltages lower than one-thousandth of a watt, according to MIT News — that’s the level of electricity that might be seen in a cell. The mesh was porous enough for the team to seed it with cells and coax them to grow. The system thereby supports cell growth while simultaneously monitoring it.

In their study, the authors used the scaffold to grow cardiac, neural and muscle tissue. They monitored heart tissue cell’s response to a stimulant called noradrenalin, which increases heart rate. Langer, who has published several groundbreaking studies on artificial tissue, nanowires and heart cells, said this could be a step toward engineered muscle: “It brings us one step closer to someday creating a tissue-engineered heart, and it shows how novel nanomaterials can play a role in this field,” he said.

08.30.2012

the starvation diet

A baby rhesus.

Remember when the starvation diet was the key to extending your life span. It seems like that is up for questioning again:

Decades of research have linked low-calorie diets with extended survival, but a new report finds that rhesus monkeys on strict diets don’t live longer than their counterparts getting a standard diet.

The findings, reported August 29 in Nature, run counter to a 2009 study from the University of Wisconsin–Madison that showed a clear survival advantage in a calorie-restricted group of similar rhesus monkeys. Scientists suspect that differences in the two studies’ designs might explain the discordant findings, leaving the question of longevity still dangling.

The median life span for a rhesus monkey in captivity is about 27 years, but some can reach age 40, says study coauthor Julie Mattison, a physiologist at the aging institute. The NIA study includes 121 monkeys, divided between calorie-restricted and standard-diet groups. Some monkeys were put on one diet or the other when they were already well into middle age. Others started on the regimen earlier in life, some very young.

Now, 23 years into the study, more than half of the monkeys have died and no survival advantage shows up from calorie restriction, the scientists report. The team considered only aging-related deaths attributable to causes such as heart disease, diabetes and cancer.

The calorie-restricted monkeys in the NIA study get about 25 to 30 percent fewer calories per day than normal, Mattison says. But she acknowledges that the control diet might also slightly underfeed the monkeys — by perhaps 5 to 10 percent fewer calories. “It may very well be that slight calorie restriction in the control animals, plus a nutritionally balanced diet,” limits the survival difference between the groups, Mattison says.

using HIV to fight cancer

A model of HIV.

HIV, like other viruses, mutates rapidly in response to changes in its environment. This ability to rapidly change gives them the ability to evade the natural defense mechanisms our bodies trigger once we are infected. Researchers have found a way to exploit this property of HIV to generate proteins that will help fight cancer. From Popular Science:

As HIV replicates, it creates slightly new versions of itself over successive generations – this allows it to readily resist most of the drug cocktails and anti-viral treatments developed to fight it. But it could also allow HIV to serve as a sort of molecule factory, creating new iterations of compounds that work in slightly different ways.

The CNRS team modified the genome of HIV by inserting a human gene for a protein called deoxycytidine kinase (dCK). This protein is found in all cells and is important for activating anti-cancer drugs. Researchers would like to make a more potent form of dCK that would allow cancer drugs to work more effectively, which could in turn require less of them, causing fewer side effects and less toxicity.

The team multiplied this mutant HIV through several generations, yielding an entire library of mutant dCK proteins, about 80 in all. Ultimately, they found a variant that induces tumor cells to die. With just 1/300th the dose of cancer-killing drugs, this one-two protein punch is just as effective at stopping tumor growth.

For more read here. For the original research paper from PLoS Genetics go here.

GOLLYGEE!

Month: August 2012 (page 1 of 3)

cyborg skin

the starvation diet

using HIV to fight cancer