Stem cells collected from human corneas restore transparency and don't trigger a rejection response when injected into eyes that are scarred and hazy, according to experiments conducted in mice by researchers at the University of Pittsburgh School of Medicine. Their study will be published in the journal Stem Cells and appears online today.

A recent special edition of the Elsevier journal Virology (www.elsevier.com/locate/viro), reviews the past, present, and future of the exciting field of small DNA tumor viruses. Many of the leaders in the field, including Dr Harald Zur Hausen, who was honored with the 2008 Nobel Prize in Medicine for his discovery of the role of human papillomaviruses in cervical cancer, contributed to this comprehensive state-of-the-art publication.

Artificial heart pacemakers have saved and extended the lives of thousands of people, but they have their shortcomings – such as a fixed pulse rate and a limited life. Could a permanent biological solution be possible?

The first antiretroviral treatments appeared in 1996. Since then, new and better drugs have been discovered that have almost turned AIDS into a chronic disease. Nevertheless, there is still room to improve the performance of the the therapeutic strategies used in clinical practice. This is shown by a study published in the online edition of The Lancet, suggesting that early administration of antiretroviral treatment reduces the rate of AIDS development and death in HIV-positive patients by 28%. This study analyzed information from more than 45,000 patients in Europe and North America and combined data from 15 international cohorts. One of these is the PISCIS Catalan and Balearic cohort, coordinated by Dr. Jordi Casabona of the Centre for Epidemiologic Studies of Sexually Transmitted Diseases and AIDS in Catalonia (CEEISCAT) - Catalan Institute of Oncology (ICO), and by Dr. Josep María Miró of the Infectious Diseases Department of Hospital Clínic - IDIBAPS, University of Barcelona. Dr. Josep María Miró is the only Spaniard in the international When to Start Consortium, which has taken part in writing and signing the article. Professor Jonathan Sterne of the University of Bristol (UK) is the first author.

Biologists at the University of Pennsylvania have revealed a hidden code that determines the expression level of a gene, providing a way to distinguish efficient genes from inefficient ones. The new research, which involved creating hundreds of synthetic green-glowing genes, provides an explanation for how a cell "knows" how much of each protein to make, providing just the right amount of protein to maintain homeostasis yet not too much to cause cell toxicity.

The DNA in the 23 pairs of chromosomes in each of the billions of cells of the human body is so tightly packed that it would measure six feet in length if stretched end to end. A genome of this size can squeeze into a cell's tiny nucleus because it is compressed into highly condensed chromatin fibers by proteins called histones.

Scorpions possess resistance to high temperatures and the ability to conserve water for long periods of time, and as a result thrive in hot and arid parts of the world. But is this global distribution also seen at a more local level? Reporting in the open-access, peer-reviewed journal PLoS ONE April 9, Doctoral student Shmuel Raz and colleagues at the University of Haifa, Israel now show that this is indeed the case, even when European-like and African-like habitats were separated by no more than 100 metres.