Posts tagged science
Oh Yeah, Developmental Biology!
Skin cells turned into healthy heart muscle cells
Scientist say they have managed to turn patients’ own skin cells into healthy heart muscle in the lab.
Ultimately they hope this stem cell therapy could be used to treat heart failure patients.
As the transplanted cells are from the individual patient this could avoid the problem of tissue rejection, they told the European Heart Journal.
Saltwater Crocodile embryos. Image 1 15 days after fertilisation. Image 2 just prior to hatching.
The saltwater crocodile (Crocodylus porosus) is the largest of allcrocodilians, and the largest reptile in the world, with unconfirmed reports of individuals up to an impressive eight to ten metres in length, although a maximum of five to six metres is more usual(2) (3) (5). The species has a relatively large head, with a pair of ridges that run from the eye along the centre of the snout. Adults are generally dark in colour, with lighter tan or grey areas, and dark bands and stripes on the lower flanks. The underside is creamy yellow to white, becoming greyer along the tail. The juvenile is usually pale tan, with black stripes and spots on the body and tail, which gradually fade with age, although never disappear entirely. Female saltwater crocodiles grow to a smaller size than males, normally reaching a maximum length of 2.5 to 3 metres (3).
With its long, powerful tail, webbed hind feet, and long, powerful jaws, the saltwater crocodile is a superbly adapted aquatic predator. As in all crocodilians, the eyes, ears and nostrils are located on top of the head, allowing the crocodile to remain almost totally submerged when lying in water, helping to conceal it from potential prey, while a special valve at the back of the throat allows the mouth to be opened underwater without water entering the throat (2) (6). The saltwater crocodile is considered to be more aquatic than most crocodilians, and is less heavily armoured along the back and neck (3).
Drug-smuggling nanoparticles target tumours
Drug-smuggling nanoparticles could be the latest recruits in the fight againstcancer. The first results from early-stage trials show that cancer drugs couriered by nanoparticles may reduce the size of tumours in humans.
Researchers from BIND Biosciences in Boston filled nanoparticles with the cancer drug docetaxel and injected them into the blood of 17 people who had cancers that are normally resistant to the drug. Forty-two days later, two of the volunteers’ tumours had shrunk in size significantly, and the rest of the volunteers’ tumours had not grown.
When injected into the body, docetaxel doesn’t discriminate between healthy and cancerous cells. However, the nanoparticles only released their payload when they reacted with molecules on the tumour’s surface, so up to 80 per cent less of the drug needed to be injected to get the same amount into the tumour.
As a result, physicians should be able to up the concentration of the drug without worrying about toxic side effects, says Jeffrey Hrkach, senior vice-president at BIND. He says larger clinical trials are in the pipeline.
Journal reference: Science Translational Medicine, DOI: 10.1126/scitranslmed.3003651
So at the California ScienCenter last week they had this.
Life-extending drug without the negative side effects
It was a bittersweet discovery: a drug that extends life but at the cost of causing diabetes. Now the drug’s dual nature has been teased apart, raising the prospect of a new life-prolonging drug without the harmful side effects.
Rapamycin is regularly given to prevent transplant rejection and treat cancer. Previous studies have also shown that it extends the life of animals, but simultaneously causes glucose intolerance – a side effect reported in humans, too.
David Sabatini of the Whitehead Institute for Biomedical Research in Cambridge, Massachusetts, and colleagues, gave the drug to strains of mice that had genes for certain proteins silenced. They found that rapamycin acts on two important nutrient-sensing proteins called MTORC1 and MTORC2. Its effect on the gene for MTORC1 prolongs life, while its action on MTORC2 causes diabetes.
Sabatini’s team is now developing variants of rapamycin that act only on the gene for MTORC1. “If we could just target MTORC1, we could preserve longevity effects and get rid of the unwanted side effects,” he says.
Human cerebral cortex development from pluripotent stem cells to functional excitatory synapses | Nature Neuroscience
Efforts to study the development and function of the human cerebral cortex in health and disease have been limited by the availability of model systems. Extrapolating from our understanding of rodent cortical development, we have developed a robust, multistep process for human cortical development from pluripotent stem cells: directed differentiation of human embryonic stem (ES) and induced pluripotent stem (iPS) cells to cortical stem and progenitor cells, followed by an extended period of cortical neurogenesis, neuronal terminal differentiation to acquire mature electrophysiological properties, and functional excitatory synaptic network formation. We found that induction of cortical neuroepithelial stem cells from human ES cells and human iPS cells was dependent on retinoid signaling. Furthermore, human ES cell and iPS cell differentiation to cerebral cortex recapitulated in vivo development to generate all classes of cortical projection neurons in a fixed temporal order. This system enables functional studies of human cerebral cortex development and the generation of individual-specific cortical networks ex vivo for disease modeling and therapeutic purposes.
(via fuckyeahneuroscience)
A montage of fluorescent microscopy images depicts pluripotent mouse stem cells that have been encouraged to develop into various kinds of specialized tissues by a mix of chemical signals. Each color combination represents a new cell type emerging from a previously uniform cell population.
Washington Post: Study suggests women's ovaries harbor rare, egg producing stem cells
WASHINGTON — For 60 years, doctors have believed women were born with all the eggs they’ll ever have. Now Harvard scientists are challenging that dogma, saying they’ve discovered the ovaries of young women harbor very rare stem cells capable of producing new eggs.
If Sunday’s report is confirmed, harnessing those stem cells might one day lead to better treatments for women left infertile because of disease — or simply because they’re getting older.
The Cell’s Muscles and Bones
Cell movement begins with lamellipodia. A thin sheet of actin filaments (light purple) that stretches out to the cell’s periphery, lamellipodia generate pushing forces that drive the cell forward. Microtubules (cyan) can barely penetrate this actin network, but they direct cell motility in other ways, such as controlling cell adhesion and acting as the cell’s internal compass.
Image: A human HaCat keratinocyte responds to epidermal growth factor by rapidly forming a lamellipod around most of its perimeter. The cell was fixed and processed within minutes after EGF addition. F-actin is stained with fluorescently labeled phalloidin (light purple), and microtubules are labeled with an antibody (cyan). DNA dye stains the nucleus dark purple.
New cancer drug sabotages tumour's escape route
Some untreatable cancers could soon be held in check by an experimental drug that targets not only the tumour itself, but also how it evolves to spread through the body.
The new drug, Cabozantinib, or cabo for short, simultaneously neutralises two mechanisms cancers need to survive. First, it chokes each tumour’s blood supply by blocking a molecule on the surface of its blood vessels, called vascular endothelial growth factor receptor (VEGFR). There is evidence in animals that cancers can respond to this kind of attack by invading new tissues, where they may be able to generate secondary tumours. Importantly, cabo foils this strategy by blocking a second receptor called c-MET that would otherwise help cancer cells spread to new tissue.
