Finding out whether you have been infected with dengue may soon be as easy as spitting into a rapid test kit. The Institute of Bioengineering and Nanotechnology (IBN) of A*STAR has developed a paper-based disposable device that will allow dengue-specific antibodies to be detected easily from saliva within 20 minutes. This device is currently undergoing further development for commercialization.

IBN Executive Director Professor Jackie Y. Ying shared, “Our rapid diagnostic kit can detect a key dengue antibody from saliva that is present in early-stage secondary infection. The ability to differentiate between primary and secondary dengue infections makes it a valuable early diagnosis tool that would help to ensure timely treatment and proper care of patients.”

Patients with secondary infection, who have previously been infected with other serotypes of dengue virus, stand a higher risk of developing dengue haemorrhagic fever or dengue shock syndrome.

According to Singapore’s National Environment Agency, dengue fever and its more severe form, dengue haemorrhagic fever, are the most common mosquito-borne viral diseases in the world. This disease poses a serious health threat, and is a leading cause of illness and death in tropical and subtropical climates. There are four known serotypes of the dengue virus, but no vaccine or medicine has been developed to treat the illness. The incubation period before symptoms develop generally ranges from 4 to 10 days after infection. Therefore, early diagnosis would enable the patient to receive prompt medical attention and avoid further complications.

Currently, dengue infection is diagnosed in the laboratory by testing the patient’s blood sample for the presence of dengue antigens or antibodies. IBN’s device, on the other hand, is capable of detecting IgG, a dengue-specific antibody found at the onset of secondary infections, directly from saliva in one step.

Unlike blood samples, saliva can be collected easily and painlessly for rapid point-of-care diagnostics. However, unlike other body fluids, it cannot be applied directly to commercially available test kits as it would cause the sensor nanoparticles to stick haphazardly to the test strip. In addition, conventional paper-based tests are not designed to handle the larger sample volume of saliva required.

As described in the journal Lab on a Chip, the IBN researchers used an innovative stacking flow design to overcome key challenges faced by existing lateral flow designs, such as those used in pregnancy test kits.

In IBN’s device, different flow paths are created for samples and reagents through a multiple stacked system. This allows the saliva sample to flow separately through a fibre glass matrix, which removes the substances that would interfere with the nanoparticle-based sensing system before it mixes with the sensor nanoparticles. IBN’s device configuration also helps to regulate the flow in the test strip, generating uniform test lines for more accurate results.

By simplifying the diagnostic procedure, the researchers hope to make the device as easy to use as over-the-counter pregnancy or fertility test kits. IBN’s oral test kit may be adapted to detect other infectious diseases. The IBN researchers are also investigating the use of other common fluid samples, such as blood, urine and serum for rapid, high-sensitivity test kits.

The Institute is currently collaborating with ARKRAY Inc., a pioneer in the field of automated analysis systems, to commercialize its paper-based diagnostic technology. In 2013, ARKRAY opened its first Asian research center outside Japan in IBN with an investment of S$9.1 million over five years. The research center is focused on developing novel detection kits for infectious diseases based on IBN’s innovative diagnostic platforms. Agency for Science, Technology and Research (A*STAR)

Scientists have proposed a new idea for detecting brain conditions including Alzheimer’s – a skin test. Their work, which is at an early stage, found the same abnormal proteins that accumulate in the brain in such disorders can also be found in skin.

Early diagnosis is key to preventing the loss of brain tissue in dementia, which can go undetected for years. But experts said even more advanced tests, including ones of spinal fluid, were still not ready for use. If they were, then doctors could treat them at the earliest stages, before irreversible brain damage or mental decline has taken place.

Investigators have been hunting for suitable biomarkers in the body – molecules in blood or exhaled breath, for example, that can be measured to accurately and reliably signal if a disease or disorder is present.

Dr Ildefonso Rodriguez-Leyva and colleagues from the University of San Luis Potosi, Mexico, believe skin is a good candidate for uncovering hidden brain disorders.

Skin has the same origin as brain tissue in the developing embryo and might, therefore, be a good window to what’s going on in the mind in later life – at least at a molecular level – they reasoned.

Post-mortem studies of people with Parkinson’s also reveal that the same protein deposits which occur in the brain with this condition also accumulate in the skin.

To test if the same was true in life as after death, the researchers recruited 65 volunteers – 12 who were healthy controls and the remaining 53 who had either Parkinson’s disease, Alzheimer’s or another type of dementia.

They took a small skin biopsy from behind the ear of each volunteer to test in their laboratory for any telltale signs of disease. Specifically, they looked for the presence of two proteins – tau and alpha-synuclein.

The 20 people with Alzheimer’s and the 16 with Parkinson’s had raised levels of both these proteins in their skin compared to the healthy controls and the patients with other types of dementia.

The people with Parkinson’s also had higher levels of alpha-synuclein protein.

Dr Rodriguez-Leyva, who will soon present his findings to the annual meeting of the American Academy of Neurology, said: ‘More research is needed to confirm these results, but the findings are exciting because we could potentially begin to use skin biopsies from living patients to study and learn more about these diseases.

‘This new test offers a potential biomarker that may allow doctors to identify and diagnose these diseases earlier on.’ It could also guide research into new treatments, he said. BBC

Scientists at The University of Texas MD Anderson Cancer Center may have discovered why some brain cancer patients develop resistance to standard treatments including radiation and the chemotherapy agent temozolomide.

Simply put, it’s all in their DNA, and it could open up new avenues for treating certain kinds of brain cancer.

DNA, the body’s essential storehouse for genetic information. In the case of glioblastoma, the most common and aggressive type of glioma or brain cancer, it can also allow the disease to progress more quickly when it is “enhanced,” allowing damaged or mutated cancer cells to repair themselves.

“A major obstacle to effective treatment is acquired resistance to treatment,” said Wei Zhang, Ph.D., professor of Pathology. “Enhanced DNA repair can allow these cancer cells to survive, contributing to resistance and tumour recurrence. We have identified Aktr3 as having the ability to robustly stimulate glioma progression.”

Akts are proteins known as kinases that regulate cell signalling. They’re involved in many bodily processes such as cell growth, cell death and tumour growth. Akts are thought to contribute to the development and progression of many cancers including prostate, breast, liver, colorectal and others. One form of this protein, Akt3, appears to be especially prevalent in the brain.

Zhang’s findings describe his team’s study results showing how Akt3 activates key DNA repair pathways.

In Zhang’s research, he reveals that Akt3 is tied to DNA’s “repair panel,” somehow boosting activation of DNA repair proteins, leading to increased DNA repair, and subsequently to cancer treatment resistance.

“This activation led to enhanced survival of brain tumour cells following radiation or treatment with temozolomide,” said Zhang. “Our work has potentially broad application to multiple cancer types in which Akt3 is expressed. Blocking this pathway may help prevent or alleviate therapeutic resistance resulting from enhanced DNA repair.” MD Anderson Cancer Center

A study by researchers at IRB Barcelona explains the basis for the classification of colon tumours in good or bad prognosis by analysing the tissue surrounding the tumour cells.

The scientists are currently developing a test that enables the identification of patients at risk of relapse after surgical removal of the tumour by measuring 4-6 genes expressed by the tumour microenvironment.

The researchers also propose to test in patients a particular drug that blocks the metastatic capacity of colorectal cancers in mice.

This drug has been tested using novel technology that allows the growth of mini colon cancers, also known as organoids, derived from patient samples.
About 40–50% of all colorectal patients relapse in the form of metastasis. In the last three years, several molecular classifications have been proposed to identify colorectal cancer patients at risk of relapse. Scientists headed by ICREA researcher Eduard Batlle at the Institute for Research in Biomedicine (IRB Barcelona) explain why these classifications work and reveal, in fact, that they can be simplified and improved by looking exclusively at the genes that are expressed in the tissue around the tumour, known as the stroma or tumour microenvironment.

“We have re-evaluated the classifications under our perspective and confirmed that colon cancer relapse occurs in patients in which tumour cells have the capacity to disrupt the tissue surrounding the tumour,” explains Eduard Batlle, head of the Colorectal Cancer Laboratory at IRB Barcelona. The team of scientists have examined the genetic profile of around 1,000 tumours from patients all over the world. “The conclusion is indisputable. The key to the classifications lies in whether the stroma of the tumour is altered or not and it is this property that confers malignancy to colon tumours. Patients with unaltered stroma are essentially cured after surgery.”

This new approach to addressing different types of colon tumour will soon have a practical application for doctors. On one hand, the scientists demonstrate that tumour cells communicate with the stroma through the hormone TGF-beta and that metastasis could be prevented in these patients by interfering with this communication. “We propose exploring the possibility of using TGF-beta inhibitors to treat colon cancer”. Several TGF-beta inhibitors are being tested for other kinds of tumours. “The data are impressive. It would be most pertinent for oncologists and pharmaceutical companies to come to an agreement in order to start clinical assays in patients with poor prognosis colon cancer” says Alexandre Calon, postdoctoral researcher and first author of the article. To test the use of these inhibitors, the scientists at IRB Barcelona have developed technology that allows them to grow mini colon tumours in vitro, also known as organoids, from samples taken from patients. “These organoids reproduce the behaviour of the original tumour and are therefore a powerful tool for personalised cancer treatment,” explains Batlle. 

Furthermore, the IRB Barcelona researchers are very close to achieving a diagnostic test named Colostage to identify those patients at the greatest risk of a relapse in the form of metastasis. “By focusing on the genetic programme of the tissue surrounding the tumour we can identify the vast majority of patients that will experience relapse. This would allow better discrimination of which patients to treat and follow up, as the use of radiotherapy or chemotherapy would benefit only this group” ensures the researcher. In addition, this test will help identify those patients more likely to benefit from the use of TGF-beta inhibitors in clinical trials. IRB Barcelona

Brown University biologists have determined how the loss of a gene in male mice results in the premature exhaustion of their fertility. Their fundamental new insights into the complex process of sperm generation may have direct applications to a similar loss of fertility in men.

What the team discovered is that the loss of the gene that makes the protein TAF4b causes a deficit in the number of progenitor cells at an embryonic stage of a male mouse’s reproductive development. Lacking those important precursor cells means that the mice struggle to develop a robust stem cell infrastructure to sustain sperm production for the long term. The affected mice are fertile at first, but quickly deplete the limited sperm supply that they can generate.

“What’s fascinating about these mice is they can reproduce,” said Richard Freiman, senior author of the new study in the journal Stem Cells. “Mice can usually reproduce until they are two years old, but these mice can only reproduce until they are four months old.”

TAF4b is a protein that affects how genes are regulated and transcribed, and its absence has profound impacts on the reproductive system. In previous work, Freiman’s research group has shown that female mice without TAF4b are totally infertile and that their ovaries age prematurely. But in experiments with males, led by lab members Lindsay Lovasco and Eric Gustafson, the effect proved more subtle.

Sperm generation follows from a complex chain of events that the research shows begins before a male mouse is even born. In their experiments, the team compared the development of mice with and without the TAF4b gene. In mice with TAF4b, progenitor cells for sperm in the male embryo arise and proliferate normally, laying the groundwork in the testes for a robust pool of spermatogonial stem cells to develop. Those stem cells are the ones that produce a renewable supply of sperm. Without TAF4b, there were fewer progenitor cells and consequently fewer stem cells. They still produce sperm at first, but they can’t renew production for the long haul. Ultimately the testes, which develop normally, become unproductive and atrophy.

What’s not yet clear from the research is why the process fades out rather than just continuing, albeit at a very low level of productivity. One possibility is the low supply of spermatogonial stem cells drives the body to invest all its meagre resources in immediate sperm production, leaving none of the stem cells in a more flexible state that can perpetually renew the supply. Another possibility is that regardless of supply, TAF4b is simply needed to see the renewal process through, for instance by maintaining some stem cells in their regenerative state.

Not only do humans have a gene for TAF4b, but a coincidental study last year in the Journal of Medical Genetics provides evidence that it also matters for sperm count. That research reported that four Turkish brothers who carried a mutation in the TAF4b gene had low sperm counts. Their mutation was in the same region of their gene as the one Freiman’s team generated in the mice.

“The human implications are very exciting,” he said. “It is possible that those men, as teenagers, were able to make functional sperm.”

Certainly more research is needed, Freiman said, but if TAF4b mutation plays out in men the way it plays out in mice, his hope is that detecting the mutation in teenage boys could allow doctors to freeze their sperm so that when they are older and want to have children, they could draw on that banked supply. Brown University