Saturday, May 25, 2013

Teeth

People may in future be able to have missing or diseased teeth replaced with ones grown from cells taken from their own mouth, scientists have predicted.
Hybrid teeth created by combining human gum cells and stem cells from mouse teeth have been grown in laboratory mice by researchers who hope the work could lead to dentures being superseded by new teeth grown on a patient's jaw.
The mixture of mouse and human cells was transplanted into adult mouse kidneys and grew into recognisable tooth structures coated in enamel with viable developing roots, according to a study published in the Journal Of Dental Research.

Two kinds of cell were used to make the bioengineered teeth. Epithelial "surface lining" cells were taken from human gum tissue and mesenchymal stem cells from the mouse embryos.
Mesenchymal cells can develop into a range of different tissues, including bone, cartilage and fat.
Professor Paul Sharpe, who led the research at King's College London's dental institute, said: "Epithelial cells derived from adult human gum tissue are capable of responding to tooth-inducing signals from embryonic tooth mesenchyme in an appropriate way to contribute to tooth crown and root formation and give rise to relevant differentiated cell types, following in-vitro culture.
"These easily accessible epithelial cells are thus a realistic source for consideration in human biotooth formation. The next major challenge is to identify a way to culture adult human mesenchymal cells to be tooth-inducing, as at the moment we can only make embryonic mesenchymal cells do this."
Previous research has shown that embryonic teeth are capable of developing normally in the adult mouth.
"What is required is the identification of adult sources of human epithelial and mesenchymal cells that can be obtained in sufficient numbers to make biotooth formation a viable alternative to dental implants," said Sharpe.

The Guardian

Trees

There are probably hundreds of famous living trees in the world. They are mostly known because of their location, age, size, unusual appearance, connections with some historical events or because of strange uses by humans. See more here.


 

Saturday, May 18, 2013

Elephants

The largest terrestrial animal

Both African elephants and Asian elephants need a lot of food and freedom to survive. They wander in small to large herds over sometimes incredibly large areas, while consuming up to several hundred kilograms of plant matter in a single day.

Elephants, in fact, place such great demands on their own environment that they frequently come into conflict with people who are competing for many of the same, often scarce, resources.

Physical description

Elephants are identified by their massive bodies and their trunk, which is used to pick a variety of objects, including food. Living members of the order Proboscidea have a maximum height of nearly 4m and a weight of up to 7,500kg. The head is large in relation to the rest of the body, and African elephants are noted for their very large ears. Hair is sparse.

The Asian elephant has four hooves (occasionally five) on the hind foot and five on the forefoot, while the African elephant has three on the hind foot and five on the forefoot.

Threats to elephants

Poaching still a problem
Although poaching of elephants for their ivory has declined since the 1989 worldwide ivory ban, it remains a widespread problem. Large quantities of African ivory, for example, are still finding their way to illegal markets in Africa and beyond. Elephants are also killed for their meat and hides.

Habitat loss also a concern

A more long-term threat is the reduction of habitat available to elephants in the face of expanding human populations. Habitat loss isolates many wild elephant populations, with ancient migratory routes cut off by human settlements.

Habitat loss and degradation also increases confrontations between elephants and people, often leading to deaths on both sides.

WWF

Friday, May 17, 2013

I've been working so hard - Van Morrison



Live to 8 track performance of "I've Been Working" recorded during the "Moondance" sessions.