New High-Resolution Method for Imaging Below the Skin Using a Liquid Lens

ScienceDaily (Feb. 20, 2011) — University of Rochester optics professor Jannick Rolland has developed an optical technology that provides unprecedented images under the skin's surface. The aim of the technology is to detect and examine skin lesions to determine whether they are benign or cancerous without having to cut the suspected tumor out of the skin and analyze it in the lab. Instead, the tip of a roughly one-foot-long cylindrical probe is placed in contact with the tissue, and within seconds a clear, high-resolution, 3D image of what lies below the surface emerges.

This prototype device developed by University of Rochester Professor of Optical Engineering Jannick Rolland can take high-resolution images under the skin's surface without removing the skin. Researchers say that in the future .it may eliminate the need for many biopsies to detect skin cancer

Rolland presented her findings at the 2011 annual meeting of the American Association for the Advancement of Science in Washington, D.C., on Feb. 19.

"My hope is that, in the future, this technology could remove significant inconvenience and expense from the process of skin lesion diagnosis," Rolland says. "When a patient walks into a clinic with a suspicious mole, for instance, they wouldn't have to have it necessarily surgically cut out of their skin or be forced to have a costly and time-consuming MRI done. Instead, a relatively small, portable device could take an image that will assist in the classification of the lesion right in the doctor's office."

The device accomplishes this using a unique liquid lens setup developed by Rolland and her team for a process known as Optical Coherence Microscopy. In a liquid lens, a droplet of water takes the place of the glass in a standard lens. As the electrical field around the water droplet changes, the droplet changes its shape and therefore changes the focus of the lens. This allows the device to take thousands of pictures focused at different depths below the skin's surface. Combining these images creates a fully in-focus image of all of the tissue up to 1 millimeter deep in human skin, which includes important skin tissue structures. Because the device uses near infrared light instead of ultrasounds, the images have a precise, micron-scale resolution instead of a millimeter-scale resolution.

The process has been successfully tested in in-vivo human skin and several papers on it have been published in peer-reviewed journals. Rolland says that the next step is to start using it in a clinical research environment so its ability to discriminate between different types of lesions may be assessed.

Rolland joined the faculty of the Hajim School of Engineering and Applied Science's Institute of Optics in 2009. She is the Brian J. Thompson Professor of Optical Engineering and is also a professor of biomedical engineering and associate director of the R.E. Hopkins Center for Optical Design and Engineering.

Efficacy of Tuberculosis Vaccine Enhanced Thanks to New Research

ScienceDaily (Feb. 19, 2011) — Nele Festjens and Nico Callewaert of VIB and Ghent University have improved the efficacy of the vaccine for tuberculosis. The new vaccine affords -- as already proven in mice -- better protection against the disease. The development of a new tuberculosis vaccine is a priority in the fight against the disease which claims the lives of 1.7 million people each year. The current vaccine provides only partial protection.

Nico Callewaert: "Our vaccine is more effective because it is more quickly recognized by the immune system of the vaccinated person. We have, as it were, undressed the existing vaccine by removing its protective shield."

Tuberculosis: a worldwide problem

One third of the world population is infected with the Mycobacterium tuberculosis bacterium which causes tuberculosis (TB). TB, AIDS and malaria are the three infectious diseases claiming the largest number of fatalities worldwide. The World Health Organization (WHO) estimates that each year 8 to 10 million people become infected. TB is in particular a disease of the poor and mainly affects young adults in their most productive years. Most TB fatalities are in the developing countries, more than half of them in Asia. In almost all of these countries, multidrug-resistant TB is becoming increasingly frequent. This form of TB is very hard to treat.

Prevention is better than cure

TB treatments are expensive and also very difficult because of multidrug-resistant TB. There has therefore been a strong focus on vaccination in the fight against TB. The only vaccine on the market is Bacillus Calmette-Guérin (BCG). It is produced from attenuated live bovine tuberculosis bacterium, Mycobacterium bovis, which has lost its virulence in humans. In children, the vaccine prevents only half of cases of tuberculosis and in adolescents and adults the degree of protection is much lower still.

In recent years, several other candidate vaccines have been developed and some of these have been tested on humans. Only a few have led to a moderate improvement in protection compared with the BCG vaccine. The search for a more efficient vaccine is therefore still on.

Removing the bacterium's defense shield

The bacterium from which the BCG vaccine is derived hides as it were from the immune system of the organism in which it ends up. This may well be the reason why the vaccine is not very effective. The fact is that a vaccine is meant to trigger an immune reaction in order to be able to afford good protection. Nele Festjens and Nico Callewaert have discovered that the bacterium hides behind the SapM enzyme that acts as a kind of shield.

They have used this knowledge to develop a new vaccine. They adapted Mycobacterium bovis BCG in such a way that it was no longer able to generate SapM and could therefore no longer hide from the immune system. Testing the new vaccine on mice has shown that it affords better protection than the present BCG vaccine.

A different mechanism

The researchers also demonstrated that their vaccine works in a way different from the other vaccines currently being tested. In fact, it acquires its extra protective value by emitting signals that provoke inflammation and in this way activate the right cells of the immune system. Festjens and Callewaert are convinced that applying their strategy -- removing the protective shield -- in the new vaccines that are somewhat better than the vaccine currently being marketed should lead to a vaccine that affords genuine protection against TB.

Conventional Wisdom of How Neurons Operate Challenged: Axons Can Work in Reverse

ScienceDaily (Feb. 19, 2011) — Neurons are complicated, but the basic functional concept is that synapses transmit electrical signals to the dendrites and cell body (input), and axons carry signals away (output). In one of many surprise findings, Northwestern University scientists have discovered that axons can operate in reverse: they can send signals to the cell body, too.

Computer-generated image representing connections between neurons. 

It also turns out axons can talk to each other. Before sending signals in reverse, axons can perform their own neural computations without any involvement from the cell body or dendrites. This is contrary to typical neuronal communication where an axon of one neuron is in contact with another neuron's dendrite or cell body, not its axon. And, unlike the computations performed in dendrites, the computations occurring in axons are thousands of times slower, potentially creating a means for neurons to compute fast things in dendrites and slow things in axons.

A deeper understanding of how a normal neuron works is critical to scientists who study neurological diseases, such as epilepsy, autism, Alzheimer's disease and schizophrenia.

The findings are published in the February issue of the journalNature Neuroscience.

"We have discovered a number of things fundamental to how neurons work that are contrary to the information you find in neuroscience textbooks," said Nelson Spruston, senior author of the paper and professor of neurobiology and physiology in the Weinberg College of Arts and Sciences. "Signals can travel from the end of the axon toward the cell body, when it typically is the other way around. We were amazed to see this."

He and his colleagues first discovered individual nerve cells can fire off signals even in the absence of electrical stimulations in the cell body or dendrites. It's not always stimulus in, immediate action potential out. (Action potentials are the fundamental electrical signaling elements used by neurons; they are very brief changes in the membrane voltage of the neuron.)

Similar to our working memory when we memorize a telephone number for later use, the nerve cell can store and integrate stimuli over a long period of time, from tens of seconds to minutes. (That's a very long time for neurons.) Then, when the neuron reaches a threshold, it fires off a long series of signals, or action potentials, even in the absence of stimuli. The researchers call this persistent firing, and it all seems to be happening in the axon.

Spruston and his team stimulated a neuron for one to two minutes, providing a stimulus every 10 seconds. The neuron fired during this time but, when the stimulation was stopped, the neuron continued to fire for a minute.

"It's very unusual to think that a neuron could fire continually without stimuli," Spruston said. "This is something new -- that a neuron can integrate information over a long time period, longer than the typical operational speed of neurons, which is milliseconds to a second."

This unique neuronal function might be relevant to normal process, such as memory, but it also could be relevant to disease. The persistent firing of these inhibitory neurons might counteract hyperactive states in the brain, such as preventing the runaway excitation that happens during epileptic seizures.

Spruston credits the discovery of the persistent firing in normal individual neurons to the astute observation of Mark Sheffield, a graduate student in his lab. Sheffield is first author of the paper.

The researchers think that others have seen this persistent firing behavior in neurons but dismissed it as something wrong with the signal recording. When Sheffield saw the firing in the neurons he was studying, he waited until it stopped. Then he stimulated the neuron over a period of time, stopped the stimulation and then watched as the neuron fired later.

"This cellular memory is a novelty," Spruston said. "The neuron is responding to the history of what happened to it in the minute or so before."

Spruston and Sheffield found that the cellular memory is stored in the axon and the action potential is generated farther down the axon than they would have expected. Instead of being near the cell body it occurs toward the end of the axon.

Their studies of individual neurons (from the hippocampus and neocortex of mice) led to experiments with multiple neurons, which resulted in perhaps the biggest surprise of all. The researchers found that one axon can talk to another. They stimulated one neuron, and detected the persistent firing in the other unstimulated neuron. No dendrites or cell bodies were involved in this communication.

"The axons are talking to each other, but it's a complete mystery as to how it works," Spruston said. "The next big question is: how widespread is this behavior? Is this an oddity or does in happen in lots of neurons? We don't think it's rare, so it's important for us to understand under what conditions it occurs and how this happens."

In addition to Spruston and Sheffield, other authors of the paper are Tyler K. Best and William L. Kath, from Northwestern, and Brett D. Mensh, from Harvard Medical School.

Two Genes Involved in Hereditary Breast and Ovary Cancer Cases

ScienceDaily (Feb. 18, 2011) — Between 5 and 10 percent of breast cancer cases are hereditary, arising because the patient inherits from the father or mother a mutation in a gene that is susceptible to causing the illness. BRCA1 and BRCA2 have already been identified as two of the genes to be monitored. It is estimated that 30 percent of hereditary breast cancer cases are due to mutations in one of these two genes (which suggests, at the same time, that there are other genes involved, but exactly how is still unknown). In any case, few of the mutations found in BRCA1 and BRCA2 could be clearly identified as pathological. The fact is that the mutations found were numerous; their variation even depending on the population.

Biologist Elena Beristain has been investigating the CAPV-EAE population. Concretely, for her study she took 521 patients mainly from the Txagorritxu hospital in the Basque capital city of Vitoria-Gasteiz, and the Cruces hospital in Barakaldo, near Bilbao: 274 patients with breast or ovarian cancer (given that the latter is also associated with mutations in the BRCA1 and BRCA2 genes), 115 family relations of these, and another 132 women who acted as a control population. Ms Beristain molecularly characterised the BCRA1 y BCRA2 genes of these individuals; apart from the exon 10 of the CHEK2 gene, also associated with the illness. Her thesis was defended at the University of the Basque Country (UPV/EHU) and it is entitled, Genetic study amongst women resident in the CAPV-EAE with hereditary breast/ovary cancer.

Could rise to 12 percent

According to the results shown, different types of variations in the genes under study have been found, including pathological ones, neutral ones and those of uncertain significance. As regards the clearly pathological mutations, the frequency is 10 percent. Nevertheless, Ms Beristain stressed that, amongst those sporadic cases of under-40s, that is a especially rare condition: only in one case was a pathological mutation found. This is why she suggested discarding under-35s in this type of research, and in which case the result arrived at in her study rises from 10 percent to 12 percent. In any case, the percentages of pathological mutations found in this genetic study of the CAPV-EAE population turned out to be less than amongst other European populations.

The study has thrown up more data regarding age. For example, the percentages show that, for family-member carriers of mutation in the main genes under study, the accumulated risk of suffering breast cancer at 70 is 69 percent for the BRCA1 and 67 percent for the BRCA2. This means that penetration is not complete and there exists the possibility that this gene does not, in the end, express itself. As regards the data on gender, it is significant that masculine breast cancer is mainly associated with mutations in the BRCA2 gene.

Different mutations in the Autonomous Community of the Basque Country

The variability from population to population in mutations in general is also clear from the results of this thesis. Ms Beristain explained that a great number of alterations, hitherto unrecorded, have been found, and from this she concludes that many of the mutations found in the CAPV-EAE are different from those described for other populations. However, she explains, amongst these, no founder effect mutation was found, i.e. there has been no case of some, many or all Basque patients coming from a small population of individuals having transmitted this common genetic characteristic to all their descendents. However it may be, the new types of mutations found represent a contribution to the already existing variability.

Como Disordered Proteínas Spread de célula a célula, potencial propagação da doença

ScienceDaily (Feb. 18, 2011) — One bad apple is all it takes to spoil the barrel. And one misfolded protein may be all that's necessary to corrupt other proteins, forming large aggregations linked to several incurable neurodegenerative diseases such as Huntington's, Parkinson's and Alzheimer's.

An image of U2OS cells infected with Q91 polygluytamine aggregates (in green) colocalized with intracelluluar expressed (red) Q25.

Stanford biology Professor Ron Kopito has shown that the mutant, misfolded protein responsible for Huntington's disease can move from cell to cell, recruiting normal proteins and forming aggregations in each cell it visits.

Knowing that this protein spends part of its time outside cells "opens up the possibility for therapeutics," he said. Kopito studies how such misfolded proteins get across a cell's membrane and into its cytoplasm, where they can interact with normal proteins. He is also investigating how these proteins move between neuronal cells.

The ability of these proteins to move from one cell to another could explain the way Huntington's disease spreads through the brain after starting in a specific region. Similar mechanisms may be involved in the progress of Parkinson's and Alzheimer's through the brain.

Kopito discussed his research on Feb. 18 at the annual meeting of the American Association for the Advancement of Science in Washington, D.C.

Not all bad

Not all misfolded proteins are bad. The dogma used to be that all our proteins formed neat, well-folded structures, packed together in complexes with a large number of other proteins, Kopito said. But over the past 20 years, researchers have found that as much as 30 percent of our proteins never fold into stable structures. And even ordered proteins appear to have some disordered parts.

Disordered proteins are important for normal cellular functions. Unlike regular proteins, they only interact with one partner at a time. But they are much more dynamic, capable of several quick interactions with many different proteins. This makes them ideal for a lot of the standard communication that happens within a cell for its normal functioning, Kopito said.

But if some of our proteins are always disordered, how do our cells tell which proteins need to be properly folded, and which don't? "It's a big mystery," said Kopito, and one that he's studying. This question has implications for how people develop neurodegenerative diseases, all of which appear to be age-related.

Huntington's disease is caused by a specific mutated protein. But the body makes this mutant protein all your life, so why do you get the disease in later adulthood? Kopito said it's because the body's protective mechanisms stop doing their job as we get older. He said his lab hopes to determine what these mechanisms are.

A bad influence

But it's clear what happens when these mechanisms stop working -- misfolded proteins start recruiting normal versions of the same protein and form large aggregations. The presence of these aggregations in neurons has been closely linked with several neurodegenerative diseases.

Kopito found that the mutant protein associated with Huntington's disease can leave one cell and enter another one, stirring up trouble in each new cell as it progresses down the line. The spread of the misfolded protein may explain how Huntington's progresses through the brain.

This disease, like Parkinson's and Alzheimer's, starts in one area of the brain and spreads to the rest of it. This is also similar to the spread of prions, the self-replicating proteins implicated in mad cow disease and, in humans, Creutzfeldt-Jakob disease. As the misfolded protein reaches more parts of the brain, it could be responsible for the progressive worsening of these diseases.

Now that we know that these misfolded proteins spend part of their time outside of cells, traveling from one cell to another, new drugs could target them there, Kopito said. This could help prevent or at least block the progression of these diseases.

Kopito is currently working to figure out how misfolded proteins get past cell membranes into cells in the first place. It is only once in the cell's cytoplasm that these proteins can recruit others. So these studies could help find ways to keep these mischief-makers away from the normal proteins.

He is also collaborating with biology professor Liqun Luo to track these proteins between cells in the well-mapped fruit fly nervous system. In the future, Kopito said he hopes to link his cell biology work to disease pathology in order to understand the role misfolded proteins play in human disease.