Tag: 9/3/21

Categories : Diseases, Syndromes and Conditions GeneticsTags :

Diphtheria Resurfacing as a Threat As it Evolves Antibiotic Resistance

On By ModernMedia

Diphtheria is resurfacing as a threat worldwide as it evolves antibiotic resistance and could escape vaccine containment, scientists warn.

Diphtheria cases in recent years have doubled what they were in previous decades, to 16 651 cases in 2018. Although babies are vaccinated against it in high-income countries, there is less coverage in middle- and low-income countries.

Diphtheria is mainly caused by Corynebacterium diphtheriae, spread by coughs and sneezes or close contact with the infected. Usually, the bacteria cause acute infections, driven by the diphtheria toxin—the main target of the vaccine. However, non-toxigenic C. diphtheria can also cause disease.

A team of researchers from the UK and India used genomics to map infections, including a subset from India, where more than half of the globally reported cases occurred in 2018.

Analysing the genomes of 61 bacteria isolated from patients and combining these with 441 publicly available genomes, the researchers were then able to understand how they spread. They also used this information to assess the presence of antimicrobial resistance (AMR) genes and assess toxin variation.

The researchers found clusters to genetically-similar bacteria isolated from different continents, most commonly Asia and Europe. This indicates that C. diphtheriae has been travelling with humans as they spread across the planet.

The diphtheria toxin ch is encoded by the tox gene, for which the researchers found 18 different variations, of which several had the potential to change the structure of the toxin.

Professor Gordon Dougan from the Cambridge Institute of Therapeutic Immunology and Infectious Disease (CITIID) said: “The diphtheria vaccine is designed to neutralise the toxin, so any genetic variants that change the toxin’s structure could have an impact on how effective the vaccine is. While our data doesn’t suggest the currently used vaccine will be ineffective, the fact that we are seeing an ever-increasing diversity of tox variants suggests that the vaccine, and treatments that target the toxin, need to be appraised on a regular basis.”

First author Robert Will, a PhD student at CITIID, said: “The C. diphtheriae genome is complex and incredibly diverse. It’s acquiring resistance to antibiotics that are not even clinically used in the treatment of diphtheria. There must be other factors at play, such as asymptomatic infection and exposure to a plethora of antibiotics meant for treating other diseases.”

Erythromycin and penicillin are commonly recommended to treat early-stage diphtheria, although there are other classes capable of it. Variants resistant to six of these classes in isolates from the 2010s were identified by the team.

Study leader Dr Ankur Mutreja from CITIID, said: “It’s more important than ever that we understand how diphtheria is evolving and spreading. Genome sequencing gives us a powerful tool for observing this in real time, allowing public health agencies to take action before it’s too late.
“We mustn’t take our eye off the ball with diphtheria, otherwise we risk it becoming a major global threat again, potentially in a modified, better adapted, form.”

Source: Medical Xpress

Journal information: Will, RC et al. Spatiotemporal persistence of multiple, diverse clades and toxins of Corynebacterium diphtheria. Nat Comms; 8 Mar 2021; DOI: 10.1038/s41467-021-21870-5

Categories : Ethics and Law General InterestTags :

Op-ed: Facebook Medical ‘Fact Checking’ Has No Room for Debate

On By ModernMedia

Fact-checking is increasingly important in an era of disinformation on social media, especially with the current COVID pandemic, but an article for MedPage Today calls into question the process for Facebook’s medical fact-checking.

After an op-ed in the Wall Street Journal by Marty Makary, MD, MPH, Johns Hopkins professor and editor-in-chief at MedPage Today, was labelled “misleading” by Facebook fact checkers, another op-ed in MedPage Today asks how the social media giant is choosing its medical fact-checkers. 

Mystified by why this would be labelled “misleading” by Facebook, and setting aside the ‘veracity’ of the article, Vinay Prasad, MD, MPH, a haematologist-oncologist and associate professor of medicine at the University of California San Francisco, investigated the website HealthFeedback.org that Facebook uses to fact-check some of its medical articles. 

The process involves two to four reviewers chosen to examine an article. Prior to the COVID pandemic, medical fact checking appears to have been done by academics, but the flood of disinformation has resulted in the change of this process, Dr Prasad noted.  

In one instance, a reviewer for the article was selected because he had already written an article critical of Dr Markary’s op-ed: in other words, he was selected because he had already announced his bias.

The website’s picking and choosing of reviewers “felt like a high school clique”, Dr Prasad wrote. One that allowed them to confirm their previously held ideas about COVID and extinguish differing viewpoints. Labelling the alternative views as misleading “instantly usurps the reader of their ability to make up their own mind. It is antithetical to the spirit of the academy.”

He found that the fact-checkers typically had large Twitter followings, while the typical medical professor seems to have them in the hundreds. This makes sense, Dr Prasad wrote, as leading academics and authorities are likely too busy to be courting large numbers of followers on Twitter.
Other than a “vague explanation” of the feedback process, Dr Prasad could not find any information on how Facebook chooses its reviewers, which of the billions of posts and articles on Facebook to fact-check, whether anyone is paid and how appeals are made.

Source: MedPage Today

Categories : Obstetrics & GynaecologyTags :

New Study Finds Marijuana THC Persists in Breast Milk

On By ModernMedia


A new study has found that tetrahydrocannabinol (THC) from marijuana can linger in breast milk for up to six weeks after ceasing marijuana use.

Marijuana is the most commonly used dependent substance in pregnancy, with up to half of users continuing through pregnancy. The use of marijuana through pregnancy is likely due to its perceived safety as well as   THC readily crosses the placental barrier, and cannabinoid receptors have been identified in both the placenta and the foetus. However, most studies done on marijuana and pregnancy dates from the 1980s –  this study is the first of its kind to examine the levels of THC in breast milk since one in 1982.

“With the increasing utilisation of marijuana in society as a whole, we are seeing more mothers who use marijuana during pregnancy,” said primary investigator Erica Wymore, MD, MPH, Neonatologist, Children’s Colorado and Assistant Professor of Pediatrics, University of Colorado School of Medicine. “However, given the lack of scientific data regarding how long THC persists in breast milk, it was challenging to provide mothers with a definitive answer regarding the safety of using marijuana while breastfeeding and simply ‘pumping and dumping’ until THC was no longer detectable in their milk. With this study, we aimed to better understand this question by determining the amount and duration of THC excretion in breast milk among women with known prenatal marijuana use.”

The researchers screened women at the Children’s Colorado and UC Health’s University of Colorado Hospital for reported marijuana use or detected THC, who were willing to abstain from marijuana for the six week duration of the study. Of the 394 women screened, 25 enrolled in the study. Seven of these women were able to abstain from their marijuana use, while the others were not able to due depending on it for stress, sleep, and pain relief.

“This study provided invaluable insight into the length of time it takes a woman to metabolise the THC in her body after birth, but it also helped us understand why mothers use marijuana in the first place,” said Maya Bunik, MD, MPH, senior investigator, medical director of the Child Health Clinic and the Breastfeeding Management Clinic at Children’s Colorado and professor of pediatrics at the CU School of Medicine. “To limit the unknown THC effects on foetal brain development and promote safe breastfeeding, it is critical to emphasise marijuana abstention both early in pregnancy and postpartum. To help encourage successful abstention, we need to look at – and improve – the system of supports we offer new moms.”

While the study was not about the impact of maternal marijuana use on childhood development, longitudinal studies dating from the 1980s show that for children born to mothers who smoked marijuana during pregnancy, there are long-term issues with cognitive and executive functioning, including impulsivity, as well as deficits in learning, sustained attention and visual problem-solving skills. One recent retrospective study has also linked marijuana use in pregnancy to autism in children. Dr Wymore points out that this is cause for concern as currently available marijuana has a potency five to six times greater than what was available prior to legalisation.

Source: News-Medical.Net

Journal information: Wymore, E.M., et al. (2021) Persistence of Δ-9-Tetrahydrocannabinol in Human Breast Milk. JAMA Pediatrics. doi.org/10.1001/jamapediatrics.2020.6098.

Categories : Cancer General InterestTags :

Impact of French Nuclear Testing Underestimated

On By ModernMedia

A new report has found that the extent of radiation exposure to people involved in nuclear testing in French Polynesia has been significantly underestimated.

Over 1966 to 1996 at Moruroa and Fangataufa atolls in French Polynesia, France conducted An unofficial report has gone through thousands of recently declassified documents, focusing on the impact of three key nuclear tests: Aldébaran, Encelade and Centaure in 1966, 1971 and 1974.
The report suggests that the French government has underestimated fallout by as much as 40%, opening the door for tens of thousands more to claim compensation.

One millisievert (mSv) per annum is the maximum allowable public exposure. There is clear evidence for radiation effects at doses over 100mSv, while doses less than 10mSv are undetectable even in very large epidemiological studies and such low dose effects on human health are controversial. According to the linear-no dose-threshold (LNT) theory, all radiation exposure carries some level of harm.

Last February, a report was sent from Paris to French Polynesia on a cluster of cancers uncovered there, believed to be linked to radiation exposure . Email evidence suggests that at least 2000 of the 6000 military personnel involved in the tests had contracted at least one form of cancer.
It was only in 2010 that France established a compensation claims board for people with one of 23 cancers associated with radiation and who lived in French Polynesia at the time of the tests. However, many claimants do not have the means to access these claims, such as those who live on remote islands.

Faulty and imprecise monitoring equipment impacted the results, which were used to calculate the original dose calculations. The researchers recalculated the estimated doses absorbed by the population based on samples taken by the military at the time, and also using new methods involving meteorological data to plot the spread of radioactive fallout. Some recalculations did not show much change, but a 1966 test produced a level three times higher than the official estimate. Some 11 000 people exposed to the nuclear testing received a dose higher than 5mSv, the researchers found.

Source: The Guardian

Categories : Cardiovascular Disease Medical Research & TechnologyTags :

New Smart Speakers That Can Remotely Monitor Heartbeat

On By ModernMedia


Smart speaker services like Amazon’s Alexa have shown that they can be adapted to monitor the breathing of babies, and recent development has enabled them to detect heartbeats without contacting the skin.

“Heart rhythm disorders are actually more common than some other well-known heart conditions. Cardiac arrhythmias can cause major morbidities such as strokes, but can be highly unpredictable in occurrence, and thus difficult to diagnose,” explained co-senior author Dr Arun Sridhar, assistant professor of cardiology at the UW School of Medicine. “Availability of a low-cost test that can be performed frequently and at the convenience of home can be a game-changer for certain patients in terms of early diagnosis and management.”

Instead of listening to the heartbeat, the smart speaker emits a continuous sound which bounces off the patient’s body. Changes in the received sound are associated with motions in the body from a heartbeat.
“The motion from someone’s breathing is orders of magnitude larger on the chest wall than the motion from heartbeats, so that poses a pretty big challenge,” said lead author Anran Wang, a doctoral student in the Allen School. “And the breathing signal is not regular so it’s hard to simply filter it out. Using the fact that smart speakers have multiple microphones, we designed a new beam-forming algorithm to help the speakers find heartbeats.”

Beam-forming is a technology where an array of emitters or receivers can change the direction in which a signal is emitted or received. Applications of such technology include directing sound only in one direction, such as a person watching TV while another wants quiet while they read,
Much in the way AI systems sort out sounds to identify human speech, the algorithm developed by the team can pick up heartbeats. As this does not produce the usual peaks seen in heartbeat monitors, this also requires processing the heartbeat further to extract the inter-beat interval.
“With this method, we are not getting the electric signal of the heart contracting. Instead we’re seeing the vibrations on the skin when the heart beats,” Mr Wang said.

The researchers tested their prototype smart speaker system on 26 healthy participants and 24 patients with hospitalised with a variety of cardiac conditions. The team compared the smart speaker’s inter-beat interval with one from a standard heartbeat monitor. Of the nearly  2,300 heartbeats measured for the healthy participants, the smart speaker’s median inter-beat interval was within 28 milliseconds of the standard monitor. With cardiac patients, the median inter-beat interval measured by the smart speaker was within 30 milliseconds of the standard.

The technology is currently set up for spot checks; a person concerned about their heart rhythm could sit in front of a smart speaker for a reading. In the future, the researchers hope that the system could be set up to monitor heartbeats for long periods, such as when they are sleeping, helping to diagnose conditions like sleep apnoea.

Source: Medical Xpress