Day: November 26, 2021

Categories : COVIDTags :

A New Variant, B.1.1.529, Emerges in South Africa

On By ModernMedia
Image by Quicknews

The National Institute for Communicable Diseases (NICD), yesterday confirmed that a new COVID variant, B.1.1.529, has been detected in South Africa. Initially detected in Botswana, 22 cases of variant B.1.1.529 have been recorded in the country following genomic sequencing. More cases are being confirmed as sequencing results come out. 

Detected cases and positivity rates are increasing quickly, particularly in Gauteng, North West and Limpopo. The UK government has acted rapidly to temporarily suspend all inbound flights from South Africa and neighbouring countries, and impose quarantines for recent arrivals.

“It is not surprising that a new variant has been detected in South Africa,” commented Prof Adrian Puren, NICD Acting Executive Director, adding that, “Although the data are limited, our experts are working overtime with all the established surveillance systems to understand the new variant and what the potential implications could be. Developments are occurring at a rapid pace and the public has our assurance that we will keep them up to date.”

‘Warp speed’ effort to track and understand variant
Dr Michelle Groome, Head of the Division of Public Health Surveillance and Response at the NICD said that provincial health authorities remain on high alert and are prioritising the sequencing of COVID positive samples.  A top priority is to track the variant more closely as it spreads: it was first identified in Botswana this month and has turned up in travellers to Hong Kong from South Africa. Scientists are also trying to determine the variant’s properties such as vaccine evasion and disease severity.

“We’re flying at warp speed,” said Penny Moore, Wits University virologist, whose lab is gauging the variant’s immunity evasion ability. While there are anecdotal reports of reinfections and cases in vaccinated individuals, “at this stage it’s too early to tell anything,” Moore cautioned.

“There’s a lot we don’t understand about this variant,” Richard Lessells, an infectious disease physician at the University of KwaZulu-Natal, said at a press briefing organised by South Africa’s health department on 25 November. “The mutation profile gives us concern, but now we need to do the work to understand the significance of this variant and what it means for the response to the pandemic.”

The variant’s apparent sharp rise in Gauteng is cause for alarm. Cases increased rapidly in the province in November, particularly in schools and among young people, according to Lessells. Genome sequencing and other genetic analysis found that the B.1.1.529 variant was responsible for all of 77 of the virus samples they analysed from Gauteng, collected between 12 and 20 November. Analysis of hundreds more samples are in the works. A previous variant, C.1.2, appeared in South Africa and had concerning mutations, but ultimately failed to replace Delta over the winter.

Fortunately, the variant has a spike mutation easily detected by fast genotyping tests as opposed to genome sequencing, according to Lessells. Preliminary data from these tests suggest that B.1.1.529 is spreading much wider than Gauteng. “It gives us concern that this variant may already be circulating quite widely in the country,” Lessells said.

Are vaccines effective against it?
As happened with the Beta variant, a similar effort is starting to study B.1.1.529. Moore’s team, which provided some of the initial data on Beta’s immunity-dodging, has begun work on B.1.1.529. They plan to test the virus’s ability to evade infection-blocking antibodies, as well as other immune responses. The variant harbours a high number of mutations in regions of the spike protein that antibodies recognise, potentially dampening their potency.

“Many mutations we know are problematic, but many more look like they are likely contributing to further evasion,” said Moore. There are even hints from computer modelling that B.1.1.529 could evade immunity conferred by T cells, Moore added. Her team hopes to have its first results in two weeks.

“A burning question is does it reduce vaccine effectiveness, because it has so many changes,” said Aris Katzourakis, who studies virus evolution at the University of Oxford, UK.

Researchers in South Africa will also study the disease severity of B.1.1.529, Lessells said, which is “the really key question”.

Sources: NICD, Nature

Categories : Gender PaediatricsTags :

Is That A Girl’s Voice or A Boy’s?

On By ModernMedia
Phot by Ben Wicks on Unsplash

Researchers have found that it is possible to distinguish a girl’s voice from a boy’s from as young as five years old, but identification requires the listener to perceive the size of the speaker, providing a clue to their likely age. 

Perceiving gender in children’s voices is of special interest to researchers, because in children, a girl’s voice and a boy’s are very similar before the age of puberty. Adult male and female voices are fairly easy to distinguish due to acoustic differences.

With children, gender perception is much more complicated because gender differences in speech may emerge before sex-related anatomical differences between speakers. This suggests listeners may need to consider speaker age when guessing speaker gender and the perception of gender may depend on acoustic information besides anatomical differences between boys and girls.

In the Journal of the Acoustical Society of America, researchers reported developing a database of speech samples from children ages five to 18 to answer two questions: What types of changes occur in children’s voices as they become adults, and how do listeners adjust to the enormous variability in acoustic patterns across speakers?

Listeners assess a speaker’s gender, age, height, and other physical characteristics based primarily on the speaker’s voice pitch and on the resonance (formant frequencies) of their voice.

“Resonance is related to speaker height — think violin versus cello — and is a reliable indicator of overall body size,” said co-author Santiago Barreda, from the University of California, Davis. “Apart from these basic cues, there are other more subtle cues related to behaviour and the way a person ‘chooses’ to speak, rather than strictly depending on the speaker’s anatomy.”
When co-authors Barreda and Peter Assmann presented listeners with both syllables and sentences from different speakers, gender identification improved for sentences. They said this supports the stylistic elements of speech that highlight gender differences and are better conveyed in sentences.

They made two other important findings. First, listeners can reliably identify the gender of individual children as young as five.

“This is well before there are any anatomical differences between speakers and before there are any reliable differences in pitch or resonance,” said Barreda. “Based on this, we conclude that when the gender of individual children can be readily identified, it is because of differences in their behavior, in their manner of speaking, rather than because of their anatomy.”

Second, they found identification of gender of speakers must take place along with the identification of age and likely physical size.

“Essentially, there is too much uncertainty in the speech signal to treat age, gender, and size as independent decisions,” he said. “One way to resolve this is to consider, for example, what do 11-year-old boys sound like, rather than what do males sound like and what do 11-year-olds sound like, as if these were independent questions.”

Their findings suggest that “perception of gender can depend on subtle cues based on behaviour and not anatomy,” said Barreda. “In other words, gender information in speech can be largely based on performance rather than on physical differences between male and female speakers. If gendered speech followed necessarily from speaker anatomy, there would be no basis to reliably identify the gender of little girls and boys.”

This study supports the notion that gender (as opposed to sex) is largely performative in nature, which has long been argued on theoretical grounds.

Source: American Institute of Physics

Categories : Respiratory DiseasesTags :

Small RNA Molecule Holds COPD Treatment Potential

On By ModernMedia
Photo by Robina Weermeijer on Unsplash

Researchers have identified a small RNA molecule called microRNA-21 as a therapeutic target and its inhibition as a potential treatment for chronic obstructive pulmonary disease (COPD). An inflammatory lung disease that makes it hard to breathe, COPD is the third most common cause of death in the world. It is often caused by smoking tobacco products or inhaling air pollution.

In the pre-clinical study which was published in Science Translational Medicine, the researchers found elevated levels of microRNA-21 in mouse models of COPD. MicroRNA-21 inhibitor (antagomir-21) as a therapeutic treatment reduced inflammation and improved lung capacity and function in these models.

The researchers said antagomir-21 both reduced microRNA-21 expression and also suppressed the influx of inflammatory cells – macrophages, neutrophils and lymphocytes – into the airways and lungs. Lung cytokine production, that amplifies inflammatory responses, was also inhibited through use of antagomir-21.

The paper’s senior author, Professor Phil Hansbro, said that their findings offered up a completely new understanding of COPD.

“MicroRNA-21 is a common molecule that is expressed in most cells in the human body and regulates many critical biological processes. Our findings demonstrate, however, that microRNA-21 levels increase when it comes to COPD,” said Professor Hansbro.

“We believe that the development of new drugs that inhibit microRNA-21 may offer up an entirely new therapeutic approach when it comes to COPD treatment.”

Professor Hansbro said that the findings may address the limited effectiveness that current therapies have in controlling COPD or halting its progression.

“The development of effective COPD treatments has been hampered by a lack of understanding of the disease’s underlying mechanisms. Our data defines microRNA-21 as a novel therapeutic target and its inhibitors as a potential new treatment for this major, currently intractable lung disease.”

Source: News-Medical.Net

Categories : CancerTags : 1 Comment

A New Understanding of How Moles Turn into Melanoma

On By ModernMedia
Melanoma cells. Source: National Cancer Institute.

Moles and melanomas are both skin tumours that come from melanocytes. Moles are usually harmless, while melanomas are cancerous and often deadly without treatment. A study published in eLife Magazine explains how common moles and melanomas form and why sometimes moles turn into melanoma.

Melanocytes produce melanin that protects the skin against UV radiation. Specific changes to the DNA sequence of melanocytes, called BRAF gene mutations, are found in over 75% of moles. The same change is also found in 50% of melanomas and is common in lung, colon and other cancers. It was thought that when melanocytes only have the BRAFV600E mutation the cell stops dividing, resulting in a mole. When melanocytes have other mutations with BRAFV600E, they divide uncontrollably, turning into melanoma. This model is called ‘oncogene-induced senescence’.

“A number of studies have challenged this model in recent years,” said Robert Judson-Torres, PhD, Huntsman Cancer Institute (HCI) researcher and University of Utah (U of U) assistant professor. “These studies have provided excellent data to suggest that the oncogene-induced senescence model does not explain mole formation but what they have all lacked is an alternative explanation – which has remained elusive.”

The study team took moles and melanomas donated by patients and used transcriptomic profiling and digital holographic cytometry. Transcriptomic profiling lets researchers determine molecular differences between moles and melanomas. Digital holographic cytometry helps researchers track changes in human cells.

“We discovered a new molecular mechanism that explains how moles form, how melanomas form, and why moles sometimes become melanomas,” said Prof Judson-Torres.

The study shows that additional mutations for melanocytes to turn into melanoma are not needed, but environmental signalling can be a trigger for the cells. Melanocytes express genes in different environments, instructing them to either divide uncontrollably or stop dividing altogether.

“Origins of melanoma being dependent on environmental signals gives a new outlook in prevention and treatment,” said Prof Judson-Torres. “It also plays a role in trying to combat melanoma by preventing and targeting genetic mutations. We might also be able to combat melanoma by changing the environment.”

These findings create a foundation for researching potential melanoma biomarkers, allowing doctors to spot cancerous changes in the blood sooner. The researchers are also keen to use these data to better understand potential topical agents to reduce risk melanoma risk, delay development, or stop recurrence, and to detect melanoma early.

Source: Huntsman Cancer Institute

Categories : Cardiovascular DiseaseTags :

Alcohol Triggers AF – But Not Caffeine or Other Likely Culprits

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Photo by Pavel Danilyuk on Pexels

Researchers have found that, out of possible triggers they tested, only alcohol use was consistently associated with more episodes of atrial fibrillation (AF). The study, published in JAMA Cardiology, did not find that the other triggers, caffeine, sleep deprivation and sleeping on the left side, to be associated with the common heart condition.

A surprising finding was that, although most of the things that participants thought to be related to their AF were not, those in the intervention group still had less arrhythmia than the people in a non self-monitoring control group.

“This suggests that those personalised assessments revealed actionable results,” said lead author Gregory Marcus, MD, MAS, professor at University of California, San Francisco. “Although caffeine was the most commonly selected trigger for testing, we found no evidence of a near-term relationship between caffeine consumption and atrial fibrillation. In contrast, alcohol consumption most consistently exhibited heightened risks of atrial fibrillation.”

Although caffeine was the most commonly selected trigger for testing, we found no evidence of a near-term relationship between caffeine consumption and atrial fibrillation.

In a brainstorming session, patients had said researching individual triggers for AF was their top priority, giving rise to the I-STOP-AFib study, which enabled individuals to test any presumed AF trigger. About 450 people participated, 58% male and 92% white.

Participants used a mobile electrocardiogram recording device along with a phone app to log potential triggers like drinking alcohol and caffeine, sleeping on the left side or not getting enough sleep, eating a large meal, a cold drink, or sticking to a particular diet, engaging in exercise, or anything else they thought was relevant to their AF. While participants were most likely to select caffeine as a trigger, there was no association with AF. Recent research has similarly failed to show a link between caffeine and arrhythmias – on the contrary, investigators found it may have a protective effect.

The new study demonstrated that consumption of alcohol was the only trigger that consistently resulted in significantly more self-reported AF episodes.

The individualised ‘n-of-1’ testing method did not validate participant-selected triggers for AF. But trial participants did report fewer AF episodes than those in the control group, and the data suggest that behaviours like avoiding alcohol could lessen the chances of having an AF episode.
“This completely remote, siteless, mobile-app based study will hopefully pave the way for many investigators and patients to conduct similar personalised ‘n-of-1’ experiments that can provide clinically relevant information specific to the individual,” said Prof Marcus.

Source: University of California, San Francisco

Categories : Implants and ProsthesesTags :

UK Man to Receive World’s First 3D-printed Eye

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Photo by Victor Freita on Pexels

A Moorfields Eye Hospital patient in the UK will be the first to benefit solely from a fully digital 3D printed prosthetic eye. Steve Verze, an engineer, will go home from the Old Street hospital with only a printed eye fitted that day. He first tried his eye on November 11 alongside a traditional acrylic prosthetic.

This new 3D printing process avoids the invasive process of making a mould of the eye socket: a procedure so difficult that in children it can require putting them under general anaesthetic.

Steve said: “I’ve needed a prosthetic since I was 20, and I’ve always felt self-conscious about it. When I leave my home I often take a second glance in the mirror, and I’ve not liked what I’ve seen. This new eye looks fantastic and, being based on 3D digital printing technology, it’s only going to be better and better.”

Professor Mandeep Sagoo, consultant ophthalmologist at Moorfields and professor of ophthalmology at the NIHR Biomedical Research Centre at Moorfields Eye Hospital UCL and Institute of Ophthalmology, said: “We are excited about the potential for this fully digital prosthetic eye.

“We hope the forthcoming clinical trial will provide us with robust evidence about the value of this new technology, showing what a difference it makes for patients. It clearly has the potential to reduce waiting lists.”

The printed eye is more realistic, with clearer definition and giving real depth to the pupil. The way light travels through the full depth of the printed eye is more natural than current prosthetics, which simply have the iris hand-painted onto a black disc embedded in the eye, with no light passage through the eye.

The current process can take six weeks but 3D printing halves that time, and the scanning ensures a precise fit. 

Source: Islington Gazette