Tag Archives: blood

London Underground polluted with metallic particles small enough to enter human bloodstream

Posted on by
Reply

The London Underground is polluted with ultrafine metallic particles small enough to end up in the human bloodstream, according to University of Cambridge researchers. These particles are so small that they are likely being underestimated in surveys of pollution in the world’s oldest metro system.

The researchers carried out a new type of pollution analysis, using magnetism to study dust samples from Underground ticket halls, platforms and operator cabins.

The team found that the samples contained high levels of a type of iron oxide called maghemite. Since it takes time for iron to oxidise into maghemite, the results suggest that pollution particles are suspended for long periods, due to poor ventilation throughout the Underground, particularly on station platforms.

Some of the particles are as small as five nanometres in diameter: small enough to be inhaled and end up in the bloodstream, but too small to be captured by typical methods of pollution monitoring. However, it is not clear whether these particles pose a health risk.

Other studies have looked at overall pollution levels on the Underground and the associated health risks, but this is the first time that the size and type of particles has been analysed in detail. The researchers suggest that periodic removal of dust from Underground tunnels, as well as magnetic monitoring of pollution levels, could improve air quality throughout the network. Their results are reported in the journal Scientific Reports.

The London Underground carries five million passengers per day. Multiple studies have shown that air pollution levels on the Underground are higher than those in London more broadly, and beyond the World Health Organization’s (WHO) defined limits. Earlier studies have also suggested that most of the particulate matter on the Underground is generated as the wheels, tracks and brakes grind against one another, throwing up tiny, iron-rich particles.

“Since most of these air pollution particles are metallic, the Underground is an ideal place to test whether magnetism can be an effective way to monitor pollution,” said Professor Richard Harrison from Cambridge’s Department of Earth Sciences, the paper’s senior author. “Normally, we study magnetism as it relates to planets, but we decided to explore how those techniques could be applied to different areas, including air pollution.”

Pollution levels are normally monitored using standard air filters, but these cannot capture ultrafine particles, and they do not detect what kinds of particles are contained within the particulate matter.

“I started studying environmental magnetism as part of my PhD, looking at whether low-cost monitoring techniques could be used to characterise pollution levels and sources,” said lead author Hassan Sheikh from Cambridge’s Department of Earth Sciences. “The Underground is a well-defined micro-environment, so it’s an ideal place to do this type of study.”

Working with colleagues from Cambridge’s Department of Materials Science and Metallurgy, Sheikh and Harrison analysed 39 dust samples from the London Underground, provided by Transport for London (TfL). The samples were collected in 2019 and 2021 from platforms, ticket halls, and train operator cabins on the Piccadilly, Northern, Central, Bakerloo, Victoria, Northern, District and Jubilee lines. The sampling included major stations such as King’s Cross St Pancras, Paddington, and Oxford Circus.

The researchers used magnetic fingerprinting, 3D imaging and nanoscale microscopy to characterise the structure, size, shape, composition and magnetic properties of particles contained in the samples. Earlier studies have shown that 50% of the pollution particles in the Underground are iron-rich, but the Cambridge team were able to look in much closer detail. They found a high abundance of maghemite particles, ranging in diameter from five to 500 nanometres, and with an average diameter of 10 nanometres. Some particles formed larger clusters with diameters between 100 and 2,000 nanometres.

“The abundance of these very fine particles was surprising,” said Sheikh. “The magnetic properties of iron oxides fundamentally change as the particle size changes. In addition, the size range where those changes happen is the same as where air pollution becomes a health risk.”

While the researchers did not look at whether these maghemite particles pose a direct health risk, they say that their characterisation methods could be useful in future studies.

“If you’re going to answer the question of whether these particles are bad for your health, you first need to know what the particles are made of and what their properties are,” said Sheikh.

“Our techniques give a much more refined picture of pollution in the Underground,” said Harrison. “We can measure particles that are small enough to be inhaled and enter the bloodstream. Typical pollution monitoring doesn’t give you a good picture of the very small stuff.”

The researchers say that due to poor ventilation in the Underground, iron-rich dust can be resuspended in the air when trains arrive at platforms, making the air quality on platforms worse than in ticket halls or in operator cabins.

Given the magnetic nature of the resuspended dust, the researchers suggest that an efficient removal system might be magnetic filters in ventilation, cleaning of the tracks and tunnel walls, or placing screen doors between platforms and trains.

Also Read:

Nasal irrigation twice a day reduces COVID-related illness, death

Exposure to air pollution in infancy alters gut microorganisms, may boost disease risk [Preventive Steps]

Soon new material to replace rogue plastic; It biodegrades in ocean water within 4 weeks

No more blood tests, now life-saving light beam to detect malaria

Posted on by
Reply

A fast, needle-free malaria detection tool developed by a University of Queensland-led team could help save hundreds of thousands of lives annually.

Malaria is usually detected by a blood test, but scientists have devised a method using a device that shines a beam of harmless infrared light on a person’s ear or finger for five-to-10 seconds, it collects an infrared signature that is processed by a computer algorithm.

International team leader, Dr Maggy Lord from UQ’s School of Biological Sciences, said the technology would revolutionise how malaria is fought globally.

The malaria detection tool collects an infrared signature for a mobile phone to process./CREDIT:The University of Queensland

“Currently it’s incredibly challenging to test large groups of people, such as the population of a village or town – you have to take blood from everyone and mix it with a reagent to get a result,” Dr Lord said.

“But with this tool we can find out very quickly whether a whole village or town is suffering from, or carrying, malaria.

“The technique is chemical-free, needle-free and detects malaria through the skin using infrared-light – it’s literally just a flash on a person’s skin and it’s done.

“The device is smart-phone operated, so results are acquired in real time.”

The researchers believe the technology is the first step to eliminating malaria.

Tiger Mosquito of Asia is adaing to survive the state of Illinois’s harsh winters / CREDIT: JAMES GATHANY/CDC

“According to the World Health Organisation malaria report, in 2020 there were an estimated 241 million cases worldwide and more than 600,000 died from malaria,” Dr Lord said.

“Most of the cases are in sub-Saharan Africa, where 90 per cent of deaths are children under five years old.

“The biggest challenge in eliminating the disease is the presence of asymptomatic people in a population who act as a reservoir for transmission by mosquitos.

“The World Health Organisation has proposed large-scale surveillance in endemic areas and this non-invasive, affordable and rapid tool offers a way to achieve that.”

The technology could also help tackle other diseases.

“We’ve successfully used this technology on mosquitoes to non-invasively detect infections such as malaria, Zika and dengue,” Dr Lord said.

“In our post-COVID world, it could be used to better tackle diseases as people move around the globe.

“We hope the tool could be used at ports of entry to screen travellers, minimising the re-introduction of diseases and reducing global outbreaks.

“It’s still early days, but this proof-of-concept is exciting.”

UQ collaborated with the Instituto Oswaldo Cruz, Brazil, led by Dr Rafael Maciel de Freitas, who applied the tool to detect malaria in patients in the Amazon region.

The work was funded by Fiocruz INOVA Ideias Inovadoras, Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico, Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de Janeiro and by Advance Queensland Industry Research Fellowship and the National Health and Medical Research Council.

Also Read:

New ecology tools predict disease transmission among wildlife, humans

Japan, India scientists develop new approach to lessen severity of malaria

Scent, sweat from human skin attract disease-spreading mosquitoes

Detecting Alzheimer’s disease in the blood using Digital ICA

Posted on by
Reply

Researchers from Hokkaido University and Toppan have developed a method to detect build-up of amyloid β in the brain, a characteristic of Alzheimer’s disease, from biomarkers in blood samples.

Alzheimer’s disease is a neurodegenerative disease, characterised by a gradual loss of neurons and synapses in the brain. One of the primary causes of Alzheimer’s disease is the accumulation of amyloid β (Aβ) in the brain, where it forms plaques. Alzheimer’s disease is mostly seen in individuals over 65 years of age, and cannot currently be stopped or reversed. Thus, Alzheimer’s disease is a major concern for nations with ageing populations, such as Japan.

A team of scientists from Hokkaido University and Toppan, led by Specially Appointed Associate Professor Kohei Yuyama at the Faculty of Advanced Life Science, Hokkaido University, have developed a biosensing technology that can detect Aβ-binding exosomes in the blood of mice, which increase as Aβ accumulates in the brain. Their research was published in the journal Alzheimer’s Research & Therapy.

Alzheimer’s disease model mice (Photo: Kohei Yuyama)./CREDIT:Kohei Yuyama

When tested on mice models, the Aβ-binding exosome Digital ICATM (idICA) showed that the concentration of Aβ-binding exosomes increased with the increase in age of the mice. This is significant as the mice used were Alzheimer’s disease model mice, where Aβ builds up in the brain with age.

In addition to the lack of effective treatments of Alzheimer’s, there are few methods to diagnose Alzheimer’s. Alzheimer’s can only be definitively diagnosed by direct examination of the brain—which can only be done after death. Aβ accumulation in the brain can be measured by cerebrospinal fluid testing or by positron emission tomography; however, the former is an extremely invasive test that cannot be repeated, and the latter is quite expensive. Thus, there is a need for a diagnostic test that is economical, accurate and widely available.

Previous work by Yuyama’s group has shown that Aβ build-up in the brain is associated with Aβ-binding exosomes secreted from neurons, which degrade and transport Aβ to the microglial cells of the brain. Exosomes are membrane-enclosed sacs secreted by cells that possess cell markers on their surface. The team adapted Toppan’s proprietary Digital Invasive Cleavage Assay (Digital ICATM) to quantify the concentration of Aβ-binding exosomes in as little as 100 µL of blood. The device they developed traps molecules and particles in a sample one-by-one in a million micrometer-sized microscopic wells on a measurement chip and detects the presence or absence of fluorescent signals emitted by the cleaving of the Aβ-binding exosomes.

Clinical trials of the technology are currently underway in humans. This highly sensitive idICA technology is the first application of ICA that enables highly sensitive detection of exosomes that retain specific surface molecules from a small amount of blood without the need to learn special techniques; as it is applicable to exosome biomarkers in general, it can also be adapted for use in the diagnosis of other diseases.

Noninvasive eye scan could detect key signs of Alzheimer’s years before patients show symptoms

These blood groups linked to your risk of stroke before age 60: Study

Posted on by
Reply

Gene variants associated with a person’s blood type may be linked to their risk of early stroke, according to a new meta-analysis published in the latest online issue of Neurology.

Non-O blood types have previously been linked to a risk of early stroke, but the new findings by University of Maryland School of Medicine study showed a stronger link between these blood types with early stroke compared to late stroke, and in linking risk mostly to blood type A.

Study author Braxton D. Mitchell of University of Maryland School of Medicine in Baltimore said, “Specifically, our meta-analysis suggests that gene variants tied to blood types A and O represent nearly all of those genetically linked with early stroke. People with these gene variants may be more likely to develop blood clots, which can lead to stroke.”

The meta-analysis involved a review of 48 studies on genetics and ischemic stroke from North America, Europe and Asia. The studies included 16,927 people with stroke and 576,353 people who did not have a stroke. Of those with stroke, 5,825 people had early onset stroke and 9,269 people had late onset stroke. Early onset stroke was defined as an ischemic stroke occurring before age 60 and late onset stroke was older than 60.

Researchers looked across all the chromosomes to identify genetic variants associated with stroke. They found a link between early stroke and the area of the chromosome that includes the gene that determines A, AB, B or O blood type.

They then divided participants into A, AB, B and O blood types. They compared the prevalence of those blood types in people with early stroke, late stroke and people who did not have a stroke.

Researchers found that people with early stroke were more likely to have blood type A and less likely to have blood type O compared to people with late stroke and people without stroke. Both early and late stroke were also more likely to have blood type B compared to controls.

Blood types/photo: en.wikipedia.org

When looking at people of European ancestry and comparing 5,825 people with early stroke to 29,320 people who did not have a stroke, the meta-analysis found that 48% of people with early stroke had blood type A compared to 45% of people with late stroke and 44% of people without stroke. They also found 35% of people with early stroke had blood type O compared to 39% of those with late stroke and 41% of people without stroke.

After adjusting for sex and other factors, researchers found those who had blood type A had an 16% higher risk of having an early stroke than people with other blood types. Those who had blood type O had a 12% lower risk of having a stroke than people with other blood types.

 

 

 

 

 

New blood test may transform the way cancer is monitored and treated

Posted on by
Reply

Stanford University scientists have described a new type of test that can detect genetic mutations in minute amounts of DNA released from cancer cells into the blood. The test, which is called single color digital PCR, requires only a fraction of a tube of blood and can detect as few as three mutation-bearing molecules in a single reaction. According to the report in The Journal of Molecular Diagnostics, this highly sensitive test has the potential to be personalized to recognize mutations unique to any individual cancer.

“For monitoring patient tumors, only a handful of blood tests are available which are limited to only several types of cancers. Nearly all cancer patients require monitoring by whole body imaging, which can be costly, complex, and time-consuming. In contrast, molecular tests like the one we have developed will enable patients to be monitored at every visit, and thus have the potential for quickly tracking cancer growth and spread. Moreover, the test’s rapid turnaround and relatively low cost, especially compared to next-generation DNA sequencing, provide a potential opportunity for universal monitoring of more patients than is currently done,” explained lead investigator Hanlee P. Ji, MD, Associate Professor in the Department of Medicine at Stanford University and Senior Associate Director of the Stanford Genome Technology Center.

The report describes the use of the test to analyze samples from six patients. Five patients were previously diagnosed with colorectal cancer and one with cholangiocarcinoma.

After generation of customized mutation detection assays, the researchers were able to identify tumor-derived circulating DNA from three out of six patients. In one patient, the assay was able to show the presence of three different mutations. The three patients, whose samples did not show elevated cancer DNA, were undergoing active treatment at the time of collection.

The single-color digital PCR test offers several advantages over other methods of circulating tumor DNA analysis, compared to next-generation targeted sequencing and fluorescent probe-based digital PCR assays. The main advantage is that the new technique does not rely on pre-amplification, which can introduce errors and biases.

“This test is simple enough to set up and analyze without extensive training, and therefore, it can be implemented by anyone, making it highly accessible to any laboratory. It has been truly motivating to work with a technology that will help transform the way that we monitor and treat individuals with cancer. I am excited to share our findings with the cancer research community,” noted lead author and researcher Christina Wood Bouwens, of the Stanford Genome Technology Center and the Division of Oncology, Department of Medicine, Stanford University School of Medicine, Stanford, California.