Tag Archives: nature

Cells play ‘tag’ to determine direction of movement

Scientists from Barcelona and London, looked at cells in the neural crest, a very mobile embryonic structure in vertebrates that gives rise to most of the peripheral nervous system and to other cell types in the cardiovascular system, pigment cells in the skin, and some bones, cartilage, and connective tissue in the head. Researchers saw that, during development, these neural crest cells ‘chase’ other types of cells — so-called placodal cells that give rise to the sensory organs — which dash away when approached, thus propelling the cell sheet in a certain direction. "The effect can also be likened to a donkey and carrot effect, with the neural crest cells — the donkey — chasing but never quite reaching the carrot, the placodal cells," explains Xavier Trepat, ICREA Research Professor of the UB and leader of the Research Group on Integrative Cell and Tissue Dynamics of IBEC…

Stem cells may be secret to regenerating fingers and toes

Mammals can regenerate the very tips of their fingers and toes after amputation, and now new research shows how stem cells in the nail play a role in that process. A study in mice, detailed online June 12 in the journal Nature, reveals the chemical signal that triggers stem cells to develop into new nail tissue, and also attracts nerves that promote nail and bone regeneration. The findings suggest nail stem cells could be used to develop new treatments for amputees, the researchers said. [Inside Life Science: Once Upon a Stem Cell] More from LiveScience In mice and people, regenerating an amputated finger or toe involves regrowing the nail. But whether the amputated portion of the digit can regrow depends on exactly where the amputation occurs: If the stem cells beneath the nail are amputated along with the digit, no regrowth occurs, but if the stem cells remain, regrowth is possible. To understand why these stem cells are crucial to regeneration, researchers turned to mice. The scientists conducted toe amputations in two groups of mice: one group of normal mice, and one group that was treated with a drug that made them unable to make the signals for new nail cells to develop. They found that the signals that guided the stem cells' development into nail cells were vital to regenerating amputated digits. By five weeks after amputation, the normal mice had regenerated their toe and toenail. But the mice that lacked the nail signal failed to regrow either their nails or the toe bone itself, because the stem cells lacked the signals that promote nail-cell development. When the researchers replenished these signals, the toes regenerated successfully. In another experiment, the researchers surgically removed nerves from the mice toes before amputating them. This significantly impaired nail-cell regeneration, similar to what happened to the mice that lacked the signals to produce new nails. Moreover, the nerve removal decreased the levels of certain proteins that promote tissue growth. Together, the results show that nail stem cells are critical for regrowing a lost digit in mice. If the same turns out to be true in humans, the findings could lead to better treatments for amputees. Other animals, including amphibians, can also regenerate lost limbs. For example, aquatic salamanders can regrow complete limbs or even parts of their heart — a process that involves cells in their immune system. By studying these phenomena in other animals, it may be possible to enhance regenerative potential in people, the researchers said. Copyright 2013 LiveScience, a TechMediaNetwork company. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.source : http://www.foxnews.com/health/2013/06/12/stem-cells-may-be-secret-to-regenerating-fingers-and-toes/

Woman paralyzed after mosquito bite

A British woman was temporarily paralyzed and confined to a wheelchair for four months after being bitten by a mosquito in Australia, the Sun reported. Days after being bitten, Natasha Porter, a 23-year-old from West Sussex, England, was unable to lift her arms. Soon after that, she was paralyzed from the neck down. Initially, doctors suspected Porter was having an allergic reaction. But Porter was eventually diagnosed with a condition called Guillain-Barré syndrome, which doctors believe was triggered by the mosquito bite, according to Nature World News. The syndrome causes the body’s immune system to attack itself. “I was so scared,” Porters said. “I remember feeling guilty, because I knew I was going to have to call my parents. I was thinking, ‘How do I call them up and say I might be dead in a few hours?’” Gradually, Porter began to regain feeling and has now made a full recovery – and plans to continue travelling the world. “I don't want to waste any time anymore, and I hope I have become a better person. I just want to live as much as I can, spend as much time with my friends and family, just enjoying my life,” Porter said. Click for more from The Sun. Click for more from Nature World News.source : http://www.foxnews.com/health/2013/06/05/woman-paralyzed-after-mosquito-bite/

Cholesterol sets off chaotic blood vessel growth

The work, led by Yury Miller, MD, PhD, associate professor of medicine at UC San Diego, will be published in the advance online edition of the journal Nature on May 29. Cholesterol is a structural component of the cell and is indispensable for normal cellular function, although its excess often leads to abnormal proliferation, migration, inflammatory responses or cell death. The researchers studied how the removal of cholesterol from endothelial cells (cells that line the blood vessels) impacts the development of new blood vessels, the process called angiogenesis. According to Miller, removal of excess cholesterol from endothelial cells is essential for restraining excessive growth of blood vessels. …

Small molecule could have big impact on cancer

In a study published online May 28 in the journal Nature Communications, Ahn and his colleagues at UT Southwestern Medical Center describe the rational design of the molecule, as well as laboratory tests that show its effectiveness at blocking the cancer-promoting function of proteins called androgen receptors. Androgen receptors are found inside cells and have complex surfaces with multiple "docking points" where various proteins can bind to the receptor. …

GATA-3 is important for regulation and maintenance of immune system

GATA-3’s role in CD4 T-cells has been widely studied, but its role in CD8+ cells has received much less attention. "We want to know what the basic function of GATA-3 in regulating cell biology is, although it has been shown that GATA-3 is important for the function of CD4+ T cell type to clear extracellular parasites," said Yisong Wan, PhD, assistant professor of microbiology and immunology at the UNC School of Medicine and member of UNC Lineberger Comprehensive Cancer Center. The research, published online May 26 by Nature Immunology, shows that GATA-3 is required for the maintenance and function of CD8+ T-cells, a T-cell type mediating the immune response to clear pathogens, eradicate tumors and promote inflammation. …

Novel class of drugs for prostate cancers

In men with advanced prostate cancer, growth of cancer cells depends on androgen receptor signaling, which is driven by androgens, such as testosterone. To thwart tumor growth, most patients with advanced prostate cancer receive drugs that block the production of androgen or block the receptor where the androgen binds. Unfortunately, such treatments invariably fail and patients die of prostate cancer with their androgen receptor signaling still active and still promoting tumor growth. In the new study, available online at Nature Communications, a team of researchers led by Dr. …

When oxygen is short, EGFR prevents maturation of cancer-fighting miRNAs

Under conditions of oxygen starvation often encountered by tumors, the epidermal growth factor receptor (EGFR) gums up the cell’s miRNA-processing machinery, an international team led by scientists at The University of Texas MD Anderson Cancer Center discovered. "So when hypoxia stresses a cell, signaling by EGFR prevents immature miRNAs from growing up to fight cancer," said senior author Mien-Chie Hung, Ph.D., professor and chair of MD Anderson’s Department of Molecular and Cellular Oncology and holder of the Ruth Legett Jones Distinguished Chair…

Researchers move closer to development of universal flu vaccine

Researchers say they have made a major step towards the development of a universal flu vaccine, after a new immunotherapy approach has shown promise in animal studies, Medical News Today reported. The method involves creating a stronger immune reaction against the flu virus in the body, protecting against more viral strains than the current vaccines do. A new flu vaccine is developed each year in order to offer the most protection against the circulating viruses.  But for the developers, it is usually a race against the clock, as the data they use quickly becomes out of date once it reaches them. Also, there is always the possibility that new flu virus strains will emerge after the vaccine has been created. The development of a universal flu vaccine would eliminate the need for the development of annual flu shots. To test their new approach, researchers from the National Institute of Allergy and Infectious Diseases (NIAID) created a vaccine that utilized a fusion of the protein ferritin, which can assemble itself into tiny nanoparticles, and the protein hemagglutinin (HA), which is found on the surface of the influenza virus.   The protein combination ultimately produced nanoparticles with eight protruding viral spikes, which served as the basis for the vaccine’s antigen – what the immune system responds to when creating antibodies. Through a series of tests on mice and ferrets, the researchers found the vaccine was more effective at boosting immunity against a much wider range of virus strains than the current flu vaccine, including strains they were not testing for. According to the researchers, the vaccine is effective because it prompts the immune system to develop antibodies to the parts of the flu virus that stay the same from strain to strain.  They say the study’s findings, published in the journal Nature, could lead to a universal flu vaccine that protects against numerous strains of the influenza virus. Click for more from Medical News Today.source : http://www.foxnews.com/health/2013/05/23/researchers-move-closer-to-development-universal-flu-vaccine/