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Novel ‘dot’ system to detect cancer


Scientists have developed a nanosystem using “quantum dots” that will help improve visualisation of tumour, paving the way for early treatment.

The nanosystem, which achieves a five-fold increase over existing tumour-specific optical imaging methods, generates bright tumour signals by delivering quantum dots to cancer cells without any toxic effects.

“Tumour imaging is an integral part of cancer detection, treatment and tracking the progress of patients after treatment,” said Kazuki Sugahara, Assistant Professor at Sanford Burnham Prebys Medical Discovery Institute (SBP) in California.

“We were able to achieve a tumour-specific contrast index between five-and 10-fold greater than the general cut-off for optical imaging, which is 2.5,” Sugahara added.

The new method utilises quantum dots — tiny particles that emit intense fluorescent signals when exposed to light — and an “etchant” that eliminates background signals.

The quantum dots are delivered intravenously and some of them leave the bloodstream and cross membranes, entering cancer cells.

Fluorescent signals emitted from excess quantum dots that remain in the bloodstream are then made invisible by injecting the etchant.

The etchant and the quantum dots undergo a “cation exchange” that occurs when zinc in these are swapped for silver in the etchant.

The silver-containing quantum dots lose their fluorescent capabilities, and because the etchant cannot cross membranes to reach tumour cells, the quantum dots that have reached the tumour remain fluorescent.

Thus, the entire process eliminates background fluorescence while preserving tumour-specific signals, the researchers said in the paper published in the journal Nature Communications.

Researchers developed the novel method using mice harbouring human breast, prostate and gastric tumours.

Quantum dots were actively delivered to tumours using iRGD, a tumour penetrating peptide that activates a transport pathway that drives the peptide along with bystander molecules — in this case fluorescent quantum dots — into cancer cells.


One avocado a day

to boost your memory


Consuming daily a fresh avocado, a nutrient-rich, cholesterol-free fruit with naturally good fats, may help boost cognitive function such as working memory and problem-solving skills in older adults, according to new research.

The findings showed that adults aged 50 and over who ate one fresh avocado a day for six months experienced a 25 per cent increase in lutein levels in their brain and eyes, which resulted in significant improvment in working memory and problem-solving skills.

Lutein is a carotenoid, or pigment, commonly found in fruits and vegetables that accumulates in the blood, eye and brain and may act as an anti-inflammatory agent and antioxidant.

“The results of this study suggest that the monounsaturated fats, fiber, lutein and other bioactives make avocados particularly effective at enriching neural lutein levels, which may provide benefits for not only eye health, but also for brain health,” said lead researcher Elizabeth Johnson from the Tufts University in Massachusetts.

Eating avacadoes also showed progressive improvement in other cognitive skills such as memory, processing speed and attention levels.

“Furthermore, the results reveal that lutein levels in the eye more than doubled in subjects that consumed fresh avocados, compared to a supplement. Thus, a balanced diet that includes fresh avocados may be an effective strategy for cognitive health,” Johnson added, in the paper published in the journal Nutrients.

In a study, researchers from the University of Texas Rio Grande Valley reported that avocado seed husks, which are usually discarded along with the seed, contain a plethora of useful chemical compounds.

The study revealed that these chemical compounds could eventually be used to treat a host of debilitating diseases as well as to enhance the allure of cosmetics, perfumes and other consumer goods.