Crossposted from Nature’s news blog on behalf of Meredith Wadman

Geron made medical history last October, when it treated subject number one in the first-ever trial of a human embryonic stem cell (hESC) therapy, for spinal cord injury.

Now, the second and third hESC trials have been launched. On July 12, in an operating room at the University of California, Los Angeles, the first subject in each of the trials — one for a rare form of blindness that usually begins in childhood, the other for a common cause of blindness in the elderly — was treated with retinal pigment epithelial (RPE) cells derived from hESCs. Details are available in this press release from the sponsoring company, Advanced Cell Technology, based in Santa Monica.

The surgery was performed by Steven Schwartz, the study’s principal investigator and retina division chief at UCLA’s Jules Stein Eye Institute, who is pictured above in the process of transplanting the cells into one of the patients on Tuesday.

Continue reading on Nature’s news blog.

US scientists today report preliminary data on a brain imaging study they say may help lead to the identification of a ‘footprint’ of post-traumatic stress disorder (PTSD) in the brain. Rajendra Morey, director of the neuroimaging lab at Durham Veterans Administrative Medical Centre, and his colleagues are presenting results of their study on 42 US soldiers who had recently served in Iraq or Afganistan at the World Psychiatric Association International Congress on Treatments in Psychiatry in Florence. Journalistically speaking, the group of probands is attractive, and so the study has been press-released in advance.

One group of 22 suffered from PTSD while a second group of 20 did not. Using an experimental paradigm designed to indicate how easily distracted the soldiers were, the neuroscientists showed that there were differences between the two groups of soldiers in activation of a brain area called the dorsal lateral prefrontal cortex, a region they say is associated with the ability to maintain vigilance. The scientists say this concords with established understanding of the underlying psychology of PTSD. Sufferers are hypervigilant, and fail to stay focussed because they are always on the look-out for unexpected threats.

They also saw also saw differences in activation in brain areas previously shown to be associated with PTSD – the medial prefrontal cortex, a large slab of tissue onto which scientists have tentatively projected many possible functions, and the amygdala, which reproducibly indicates the emotional saliency of a signal (ie ‘is what I am seeing or hearing truly appalling, or is it not quite so bad?’)

What do the results tell us? Primarily that it is possible to see group differences in brain activation patterns between people with PTSD and those without it. It is a solid piece of information, but the hope of eventually finding a useful and reliable way of predicting an individual’s susceptibility to PTSD, or to diagnosing it – as expressed in the meeting abstract – is still just a hope. This is part of a body of work which is very much in progress. Seeing group differences is a long way from being able to predict syndromes from an individual’s brain scan. For many reasons, individual brain scans are still highly variable.