Study uncovers mechanics of machete-like ‘tail-whipping’ in thresher sharks

Peer-Reviewed Publication

FLORIDA ATLANTIC UNIVERSITY

 

VIDEO: 

A THREE-QUARTER VIEW OF A MICRO-CT SCANNED VERTEBRAL COLUMN SEGMENT AND A SINGLE MICRO-CT SCANNED VERTEBRA OF A COMMON THRESHER SHARK. IN THE THRESHER COLUMN, THE FRONTMOST VERTEBRA IS A TRANSVERSE CROSS-SECTION DISPLAYING FOUR SECTORS OF MINERALIZED MICROSTRUCTURE. THE VIDEO "DIGITALLY DISSECTS" INTO THE SEGMENT TO SHOW A SAGITTAL CROSS-SECTION OF THE CONSECUTIVE VETERBRAE. IN THE SINGLE THRESHER VERTEBRA, THE VIDEO DISSOLVES THE ANTERIOR FACE OF THE VERTEBRA TO SHOW THE INTRICATE MICROSTRUCTURE QUANTIFIED IN THE STUDY. 

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CREDIT: FLORIDA ATLANTIC UNIVERSITY

Like Indiana Jones, thresher sharks (Alopias spp.) have mastered the art of the whip using their tails. With incredible speed, their long, machete-like tails can slap and stun their prey, allowing them to swallow multiple fish in one fell swoop. Their exceptionally elongated tail, which can often be as long as their entire body, not only makes this particular shark unique, but also a formidable hunter.

Thresher shark “tail-whipping” consists of four phases: preparation, strike, wind-down recovery, and prey collection. Overhead tail slaps begin in the preparation phase by lunging toward targeted prey. The strike phase begins by lowering the head and flexing the body, which raises the tail over their head to create a whip-like motion. The wind-down recovery phase consists of the shark returning to swimming posture, and consuming stunned prey.

The shark’s tail-whipping movement dramatically differs from the side-to-side motion produced by its body during swimming. The cartilaginous vertebral column, which is the main body axis, may have anatomical modifications to withstand the extreme bending during the tail-whipping behavior. Prior research has examined the vertebrae of thresher sharks, but in the context of the forces experienced during swimming.

Now, new research from Florida Atlantic University in collaboration with Apex Predators Program, Northeast Fisheries Science Center, National Oceanic and Atmospheric Administration (NOAA), provides intricate details showing that anatomy of the vertebrae might support the mechanics of extreme body bending in thresher sharks, enabling these expert hunters to weaponize their tails.     

For this study, researchers examined vertebrae from the head and tail ends of the body. They investigated vertebral anatomy and measured variables like height, width and length along the vertebral column from 10 common thresher sharks (Alopias vulpinus) across a range of sizes from an embryo to large adults.

Researchers used micro-CT scanning, similar to CAT scans humans use in medical facilities, to image the internal architecture of each vertebra and quantified various mineral structures found in the calcified cartilage. They also used two-dimensional shape analysis techniques to examine variation in the spatial distribution of mineral structures along the vertebral column.

Results of the study, published in the journal Royal Society Open Science, suggest thresher shark vertebral anatomy and mineralized microstructure meet the demands required for fast swimming and tail-whipping behavior seen in these species.

Researchers found that the mineralized microarchitecture in thresher shark vertebrae changes in the front and the back of the body, and these anatomical modifications may support their unique tail-whipping behavior. Essentially, thresher shark vertebral column is fortified along its length and might work like a catapult, allowing the tail to launch over the head.

“We found that anatomy and microstructure significantly varied along the body and among developmental groups – embryonic, juvenile and adult common thresher sharks,” said Jamie L. Knaub, first author and a doctoral graduate student in FAU’s Department of Biological Sciences within the Charles E. Schmidt College of Science. “Based on our results, we believe that thresher shark vertebrae vary in anatomy, and the amount and arrangement of mineral, supporting the mechanical needs for tail-whipping.”

The researchers also discovered that juvenile-sized sharks acquire mineralized structures throughout development, likely to support a larger body as they grow and tail for whipping behaviors. 

“We think that anterior body vertebrae stabilize the thresher shark’s main body, while vertebrae closer to the tail support overhead tail-whips,” said Marianne E. Porter, Ph.D., senior author and an associate professor, FAU Department of Biological Sciences. “Additionally, developmental changes suggest that vertebral anatomy shifts across development to support a larger body and caudal fin.”

Thresher sharks, part of the Alopiidae family, comprise three species: the pelagic thresher (Alopias pelagicus), the bigeye thresher (Alopias superciliousus), and the common thresher (Alopias vulpinus). All three thresher shark species have been listed as vulnerable to extinction by the World Conservation Union since 2007.

 Study co-authors are Michelle Passerotti, Ph.D., a fish biologist, Apex Predators Program, NOAA Fisheries; Lisa J. Natanson, Ph.D., a shark researcher, Apex Predators Program, NOAA Fisheries (retired); and Tricia Meredith, Ph.D., director of research, FAU A.D. Henderson University School and FAU High School, and an assistant research professor, FAU College of Education.

The work was conducted as part of Knaub’s Ph.D. research, which was supported by a National Science Foundation (NSF) CAREER grant awarded to Porter (NSF, IOS-1941713), the Jim Elliot Award from Tomography for Scientific Advancement awarded to Knaub, and the Vincent Saurino Fellowship, the Newell Doctoral Fellowship, and the National Save the Sea Turtle Foundation Scholarship from FAU awarded to Knaub.

- FAU -

About Florida Atlantic University:
Florida Atlantic University, established in 1961, officially opened its doors in 1964 as the fifth public university in Florida. Today, the University serves more than 30,000 undergraduate and graduate students across six campuses located along the southeast Florida coast. In recent years, the University has doubled its research expenditures and outpaced its peers in student achievement rates. Through the coexistence of access and excellence, FAU embodies an innovative model where traditional achievement gaps vanish. FAU is designated a Hispanic-serving institution, ranked as a top public university by U.S. News & World Report and a High Research Activity institution by the Carnegie Foundation for the Advancement of Teaching. For more information, visit www.fau.edu.

Micro-CT scanned thresher shark vertebral column. 

A micro-CT scan of a single vetebra in a common tresher shark. 

CREDIT

Florida Atlantic Universit

JOURNAL

Royal Society Open Science

DOI

10.1098/rsos.231473 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Vertebral morphology in the tail-whipping common thresher shark, Alopias vulpinus

ARTICLE PUBLICATION DATE

3-Jan-2024

 

New research finds half-cardio, half-strength training reduces cardiovascular disease risks

Peer-Reviewed Publication

IOWA STATE UNIVERSITY

AMES, Iowa — Approximately one in three deaths in the U.S. is caused by cardiovascular disease, according to the U.S. Centers for Disease Control and Prevention. A robust body of evidence shows aerobic exercise can reduce risks, especially for people who are overweight or obese. But few studies have compared results with resistance exercise — also known as strength or weight training — or with workout regimens that are half aerobic and half resistance. Researchers at Iowa State University led one of the longest and largest supervised exercise trials to help fill this gap.

Their results, published in European Heart Journal, indicate that splitting the recommended amount of physical activity between aerobic and resistance exercise reduces cardiovascular disease risks as much as aerobic-only regimens. Resistance exercise on its own for the same amount of time did not provide the same heart health benefits when compared to the control group.

“If you’re bored with aerobic exercise and want variety or you have joint pain that makes running long distances difficult, our study shows you can replace half of your aerobic workout with strength training to get the same cardiovascular benefits. The combined workout also offers some other unique health benefits, like improving your muscles,” says Duck-chul Lee, lead author and professor of kinesiology at Iowa State.

Performing a certain number of sets and repetitions with weight machines, free weights, elastic bands or your own body weight through push-ups or lunges, all fall under resistance exercise.

“One of the most common reasons why people don’t exercise is because they have limited time. The combined exercise with both cardio and strength training we’re suggesting is not more time consuming,” Lee underscores.

Co-authors from Iowa State include Angelique Brellenthin, associate professor of kinesiology; Lorraine Lanningham-Foster, department chair and associate professor of food science and human and nutrition; Marian Kohut, the Barbara E. Forker Professor in kinesiology. Yehua Li, professor of statistics at the University of California Riverside, also contributed.

In the paper, they wrote: “These findings may help develop clinical and public health practices and recommendations for the approximately 2 billion adults with overweight or obesity worldwide who are at increased risk of [cardiovascular disease.]”

One of the longest, largest exercise trials

Four hundred and six participants between 35 and 70 years of age enrolled in the one-year randomized controlled exercise trial. All met the threshold for being overweight or obese with body mass indexes between 25-40 kg/m2 and had elevated blood pressure.

The researchers randomly assigned participants to one of four groups: no exercise, aerobic only, resistance only, or aerobic plus resistance. Those who were in one of the three exercise groups worked out under supervision for one hour, three times a week for one year.

Every participant in one of the exercise groups received a tailored workout routine based on their individual fitness levels, health conditions and progression. Those assigned to resistance training were given a certain number of sets, repetitions and weights for weight-lifting machines. With aerobic exercises, participants wore a heart rate monitor and inserted a unique exercise program key into a treadmill or stationary bike. Sensing the participant’s heart rate, the machine automatically adjusted the speed and grade to match the prescribed intensity.

Researchers collected physical activity and diet data outside the lab, as well. All participants, including those in the no exercise group, wore pedometers to measure daily steps. They met every three months with registered dietitians at Iowa State for “Dietary Approaches to Stop Hypertension” education, which is promoted by the National Institutes of Health. On three random days per month, participants were asked to record what they had consumed in the last 24 hours with an online dietary assessment tool developed by the U.S. National Cancer Institute.

At the start of the year-long clinical trial, six months in and at the end, the researchers measured each participant’s systolic blood pressure, low-density lipoprotein cholesterol, fasting glucose and body fat percentage. All are well-established cardiovascular disease risk factors.

“Many previous studies only looked at one of these four factors, but it’s really multiple factors combined that increase cardiovascular disease risk,” explains Lee.

The researchers used a composite score to fairly quantify changes across all four factors since each uses a different unit of measurement. A lower composite score indicates less risk for developing cardiovascular disease.

Main findings

At the end of the year-long trial, the percentage of body fat in all three exercise groups had decreased significantly compared to the no-exercise control group. The authors write in the paper that “every -1% body fat reduction is associated with -3%, -4%, and -8% lower risks of developing [cardiovascular disease] risk factors of hypertension, hypercholesterolemia, and metabolic syndrome.”

However, taking all four cardiovascular disease risk factors into account, the aerobic and combined exercise groups had lower composite scores than the control group. The results were consistent across gender and age.

Secondary findings

Over the course of the 12-month study, those in the aerobic-only group continued to improve with the VO2max test, which is the maximum rate of oxygen consumption attainable during a maximal treadmill test. The resistance-only group stayed relatively flat. The inverse was true for the maximal bench and leg press tests for muscular strength; the resistance-only group continued to improve while the aerobic-only group did not.

However, the combination exercise group improved both aerobic fitness and muscular strength.

Finding the right dose

The authors say their findings support “physical activity guidelines recommending both resistance and aerobic exercise by the U.S., [World Health Organization] and European Society of Cardiology, specifically for individuals with obesity.” Currently, it’s at least 150 minutes each week of moderate intensity aerobic exercise and two sessions per week of resistance training.

“But these guidelines don’t specify how long those strength training sessions should be to get the health benefits,” says Lee.

With a newly awarded grant from the National Heart, Lung and Blood Institute, Lee wants to find “the right dose” of resistance exercise among adults who are overweight or obese. He plans to conduct another randomized controlled resistance exercise trial, this time with 240 participants. The study will compare results from 0-, 15-, 30- and 60-minute resistance sessions, twice per week for six months in a supervised exercise lab. Participants in all four groups also will be asked to do 30-minute sessions of moderate intensity aerobic exercise, twice per week, per the physical activity guidelines.

During the second six-month phase, participants will receive a free health club membership and be asked to continue their assigned regimen, unsupervised. Lee explains this will help identify which dose of resistance exercise is both effective and feasible outside experimental trials.

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JOURNAL

European Heart Journal

METHOD OF RESEARCH

Randomized controlled/clinical trial

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Aerobic, resistance, or combined exercise training and cardiovascular risk profile in overweight or obese adults: the CardioRACE trial

ARTICLE PUBLICATION DATE

17-Jan-2024

 

PSE Healthy Energy awarded grant from the California Energy Commission

Scientists to evaluate social costs and non-energy benefits of California’s clean energy goals

Grant and Award Announcement

PSE HEALTHY ENERGY

OAKLAND, CA – The California Energy Commission (CEC) has selected PSE Healthy Energy to support their development of social cost and non-energy benefit metrics for the deployment of clean energy resources. These metrics will be used to evaluate scenarios for achieving California’s clean energy goals, including through California’s 100 percent clean energy target, as defined in Senate Bill 100 (SB100).

“Transitioning to 100 percent renewable and zero-carbon electricity resources by 2045 will reshape California’s energy systems,” says PSE Healthy Energy Senior Scientists Patrick Murphy. “By helping identify the potential non-energy costs and benefits of this transition, we hope to advance strategies that achieve our climate goals and maximize the benefits for public health, the environment, equity, and resilience.”

Under the contract, PSE Healthy Energy will partner with HR&A Advisors and George Washington University to analyze key factors likely to be impacted by the clean energy transition, including land-use impacts, air quality, water supply and quality, and economic and affordability impacts. The team will consider public health, equity, and resilience as cross-cutting factors. The team will work closely with the CEC to coordinate other government stakeholders and the public in order to develop standard approaches for incorporating these social costs and non-energy benefits into existing and future planning processes and frameworks. 

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About PSE Healthy Energy

PSE Healthy Energy (PSE) is a scientific research institute generating energy and climate solutions that protect public health and the environment. PSE provides expertise in public health, environmental science, and engineering and brings science to energy policy through actionable research, communications, and advising. Visit us at psehealthyenergy.org and follow us on X @PhySciEng.

 

Texas A&M AgriLife Research gets $5.2 million grant for onion improvement

National Institute of Food and Agriculture-funded project will address multiple aspects of successful short-day onion production

Grant and Award Announcement

TEXAS A&M AGRILIFE COMMUNICATIONS

Texas A&M AgriLife Research received more than $5.2 million in grant funding from the U.S. Department of Agriculture’s National Institute of Food and Agriculture for a project to address multiple aspects of the southern U.S. onion harvest system.

 

Subas Malla, Ph.D., Texas A&M AgriLife Research associate professor at the Texas A&M AgriLife Research and Extension Center in Uvalde, will serve as director for a short-day onion project. (Texas A&M AgriLife photo by Paul Schattenberg)

The director for the “Ensuring Future Economic Viability of U.S. Short-Day Onion Production Through Mechanical Harvesting” project will be Subas Malla, Ph.D. Malla is an AgriLife Research associate professor of vegetable breeding at the Texas A&M AgriLife Research and Extension Center in Uvalde.

The Texas A&M AgriLife team is comprised of Stephen Searcy, Ph.D., Professor Emeritus and former head of the Department of Biological and Agricultural Engineering, Bryan-College Station; Juan  Anciso, Ph.D., professor and Texas A&M AgriLife Extension Service vegetable specialist, Weslaco; Francisco Abello, Ph.D., assistant professor and AgriLife Extension economist – management, Vernon; and Larry Stein, Ph.D., professor, Regents Fellow and associate head of the Department of Horticultural Sciences, Uvalde. The University of California, the University of Georgia and New Mexico State University will also partner on the project.

Searcy will serve as co-director and lead the project’s agricultural engineering research. Anciso and Abello will lead the AgriLife Extension and economic analysis components, respectively.

“The goal of this proposal is to improve profitability and ultimately market share for short-day onions by mechanizing short-day onion harvesting,” Malla said. “We intend to do this through development and selection of cultivars, optimization of production practices, improved harvest systems, and communication of the associated socioeconomic benefits to growers and packers.” 

Short-day onions long on production challenges

The majority of onions grown across the southern region of the U.S. are short-day onions. Short-day onions require about 10-12 hours of daylight to produce bulbs, while long-day onions require 14-16 hours.

 

In 2023, the fresh market onion industry grew a total of 75,460 tons across 7,158 acres in 35 South Texas counties. (Texas A&M AgriLife photo by Laura McKenzie)

According to South Texas Growers Inc., a wholesale nursery, in 2023, the state’s fresh market onion industry — sweet, yellow, red and white onions combined — grew a total of 75,460 tons across 7,158 acres in the 35 South Texas counties. The average farm-gate value of those onions is around $39 million. 

Short-day onions are a high-value vegetable crop in many southern U.S. states, including Texas, but their biology and structure present some difficulties, especially during harvest.

Onion harvesters developed for long-day onions in northern states have been tested with short-day onions, Searcy said, but growers judged the results to be less than satisfactory.

“Dry matter content in the short-day sweet onion is low but the water content is high,” Malla said. “Due to the high water content in the bulb, there is a greater likelihood of bruise damage since the bulbs can’t withstand a higher-pressure impact when harvested. That is why short-day onions have traditionally been harvested by hand.”

In efforts to use mechanized harvesting, too many bulbs were damaged to be acceptable for the fresh market, he said.

“However, these past attempts were limited to substituting the mechanical harvester for manual labor and did not involve a whole-system approach.”

The new project aimed at mechanizing harvest will involve the whole system and include short-day onion areas in Georgia, Texas, New Mexico and California to represent a full range of growing conditions.

“Limited availability and increasing cost of labor has resulted in decreased U.S. short-day onion production and a lack of competitiveness with foreign sources,” Malla said. “A viable mechanized harvest system is a high priority for growers and the industry.”

Building a better short-day onion harvest system 

Malla said the project will address the many facets of developing a successful harvest system. These include:

–  Identifying cultivars and production practices suitable for mechanical harvesting.

–  Modifying the harvest system to minimize the potential damage to onion bulbs.

–  Evaluating the influence of mechanical harvest on profitability and risk faced by onion growers.

–  Communicating the benefits and drawbacks of adopting mechanical harvesting to growers.

Malla said the adoption of any advances by growers will rely on partnerships with equipment manufacturers, seed companies and technology providers. A stakeholder advisory panel and scientific advisers will participate in the project’s proposed research and outreach activities.

“We are already in the process of evaluating diverse Texas A&M onion germplasm to understand the genetic mechanism of host resistance against diseases and insects,” Malla said. “We are working with the Texas A&M Vegetable and Fruit Improvement Center to test bulb quality and storability in onions. We are also testing Texas A&M onion germplasm in a way that will help shorten the cultivar development cycle.”

To his knowledge, Malla said, this project is one of the broadest and most comprehensive ever undertaken to address the many challenges to short-day onion production.

“Our ultimate goal is identifying the best cultivars and improving the short-day onion harvest system in a way that provides better results and better profitability for the producer,” he said.    

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DECRIMINALIZE DRUGS

UQ leads the world’s largest drug survey

Researchers from The University of Queensland have launched the world’s biggest drug survey, to gain insight into drug use around the globe.

Reports and Proceedings

UNIVERSITY OF QUEENSLAND

Researchers from The University of Queensland have launched the world’s biggest drug survey, to gain insight into drug use around the globe.

The Global Drug Survey was founded by Professor Adam Winstock from University College London and has been running annually since 2012.

This year the survey is led by Dr Cheneal Puljevic from UQ’s School of Public Health.

“The aim of the Global Drug Survey is to make drug use safer for people, regardless of the drug’s legality,” Dr Puljevic said.

“We hope to gain insight into drug use across the world, so we can inform individuals and organisations about what’s going on in their communities and how best to reduce harms from drug use.”

This year respondents will be asked about drug prices, decriminalisation, tobacco endgame policies, performance and image enhancing drugs, nitrous oxide use and drug use in nightlife and festival settings.

It will also be the first Global Drug Survey to ask questions about the use of illicit tobacco.

Dr Puljevic said there had been very little international research into the tobacco black market.

“Illegal tobacco use has exploded in the past year, with some tobacconists in Australia selling packets of cigarettes for as little as $5,” she said.

“But we don’t really know much about who’s using illicit tobacco or where they're getting it from.”

The 2024 survey also includes questions about how peoples’ drug use would change if drugs like MDMA and cocaine were decriminalised.

The anonymous online survey has been translated into 9 different languages and will be circulated worldwide.

It takes between 20 to 30 minutes to complete.

“The Global Drug Survey usually gets more than 100,000 respondents from more than 25 countries, so our goal is to exceed that this year,” Dr Puljevic said.

“We want as many diverse perspectives as possible, with respondents of all ages, genders and sexual orientations and from rural and urban areas.”

The Global Drug Survey 2024 will run until 30 April and can be completed here.

Dark web fentanyl-selling operations have grown rapidly, offer steep discounts

Study highlights the challenges of limiting supply by shuttering online purveyors

Peer-Reviewed Publication

CARNEGIE MELLON UNIVERSITY

Overdose deaths in North America have skyrocketed, primarily because of the spread of illegally manufactured fentanyl. In a new study, researchers analyzed an early and prominent fentanyl-selling operation on the dark web. The organization sustained a significant growth rate, which allowed it to offer consumers steep discounts. In light of these findings, the authors conclude that it might be challenging to constrain supply by shuttering individual organizations since remaining organizations could grow rapidly to fill unmet demand.

The study was conducted by researchers at Carnegie Mellon University, the University of Arizona, Tucson, and the University of Maryland, College Park. It appears in Global Crime.

“Internet drug sales have the potential to become more prevalent,” explains Jonathan P. Caulkins, professor of operations research and public policy at Carnegie Mellon’s Heinz College, who led the study. “This raises the question of how they differ from traditional in-person distribution systems; to answer that, we examined how the organization operated, how profitable it was, and what its vulnerabilities were.”

For the first time, researchers used both detailed qualitative and large-scale transaction-level data to analyze more than 5,500 drug transactions involving more than 870,000 items sold for about $2.8 million through AlphaBay; the AlphaBay marketplace operated from 2014 to 2017 and was considered the largest dark web marketplace, with more than 200,000 users. Dark web marketplaces, like legal Internet marketplaces such as eBay and Amazon, allow vendors and buyers exchange currency for goods, with orders fulfilled primarily by contracting with parcel delivery services. However, dark web marketplaces (also called cryptomarkets) generally involve cryptocurrencies, which provide anonymity.

The study focused on a prominent organization based in Utah that primarily manufactured counterfeit prescription pills containing fentanyl and distributed them by U.S. mail. This organization is of particular interest because it allowed the researchers access to seller-level data, providing insights into organizational strategy. The study also analyzed court documents related to the prosecution of the organization. Operating at least between July 2015 and November 2016, the organization used the storefront name Pharma-Master. Most of Pharma-Master’s sales were of counterfeit oxycodone pills, which contained fentanyl but no oxycodone.

Pharma-Master sustained a sales growth rate of approximately 15% per week, the study found. Increasing order sizes by a factor of 10 reduced the price per pill by approximately 25% for oxycodone and 50% for Xanax, which the organization also sold. Those steep quantity discounts led to large price markups when selling further down the distribution chain.

The authors suggest that drug trafficking organizations’ high growth rates and price markups make it hard for law enforcement to shut down organizations quickly enough to prevent other organizations from expanding to fill unmet consumer demand. They also conclude that:

• Organizations selling via internet drug markets can share characteristics with legal firms (e.g., they are profit-making entities that regularly produce and sell products to customers, their staff has specialized roles, and ownership operates separately from workers), but differ from organizations that sell drugs in traditional drug markets (e.g., they may recruit employees from an inner circle of friends and acquaintances who lack prior criminal convictions or connections to drug distribution).
   
• Internet drug traffickers can expand rapidly, in part because they are not limited by geography.
   
• Online selling can be profitable because of low costs and the ability to reach many customers at multiple levels of the market without having to conduct in-person meetings, which can be risky.

Among the study’s limitations, the authors note that they are uncertain what proportion of Pharma-Master’s sales are represented in the data they analyzed, so these data may represent only about a quarter to a half of all the organization’s actual transactions. In addition, Pharma-Master may have been atypical: Most online vendors are small and short-lived. Finally, market conditions have changed since 2016, with most fentanyl now entering the United States from Mexico, not directly from China.

“Pharma-Master was just one drug-trafficking organization and while it was a successful one, it was not long-lived,” notes Philippe C. Schicker, who coauthored the study while he was a master’s student in public policy and data analytics at Carnegie Mellon’s Heinz College. “But there is still significant value in studying this organization because it contributed to the early rise in manufacturing counterfeit prescription drugs containing fentanyl, which has dominated drug overdose deaths in the United States and Canada for several years.”

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JOURNAL

Global Crime

DOI

10.1080/17440572.2023.2291352 

ARTICLE TITLE

A detailed study of a prominent dark web fentanyl trafficking organization

Nationwide study suggests link between medical cannabis for chronic pain and abnormal heart rhythm

Peer-Reviewed Publication

EUROPEAN SOCIETY OF CARDIOLOGY

 

IMAGE: 

PORTRAIT PHOTO OF RESEARCHER DR ANDERS HOLT

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CREDIT: EUROPEAN HEART JOURNAL / ANDERS HOLT

People taking medical cannabis for chronic pain have a slightly increased risk of arrhythmia, according to research published in the European Heart Journal [1] today (Thursday). Arrhythmia is when the heart beats too slowly, too quickly or irregularly. It includes conditions like atrial fibrillation.

 

Recreational use of cannabis has been linked to cardiovascular disease but there has been very little research on the side effects of medical cannabis.

 

Researchers say the new study is important as a growing number of countries now permit medical cannabis as a treatment for chronic pain.

 

The study was led by Dr. Anders Holt from Copenhagen University Hospital – Herlev and Gentofte in Denmark.  It included data on 5,391 Danish patients who had been prescribed cannabis for chronic pain. This included people with pain in their muscles, joints or bones, people with cancer and those suffering with nerve pain. Researchers compared this group with 26,941 patients who also had chronic pain but were not receiving cannabis as a treatment.

 

The data showed that patients receiving medical cannabis had a 0.8% risk of being diagnosed with arrhythmia that required monitoring and possible treatment within 180 days of receiving cannabis. This risk was more than twice the risk for patients with chronic pain who were not taking cannabis. The difference in risk between the two groups had become smaller when researchers looked at the first year of treatment.

 

Patients taking cannabis who were aged 60 and older and those already diagnosed with cancer or cardiometabolic disease, such as heart disease, stroke and diabetes, had the largest increases in their risk of arrhythmia.

 

The study did not show any link between taking medical cannabis and the risk of acute coronary syndrome, which includes a heart attack and unstable angina, stroke or heart failure.

 

Dr. Holt said: “Medical cannabis is now allowed as a treatment for chronic pain in 38 US states as well as several countries in Europe – such as Spain, Portugal, the Netherlands and the UK – and elsewhere around the world. This means more and more doctors will find themselves prescribing cannabis, despite a lack of evidence on its side effects.

 

“I don’t think this research should make patients with chronic pain refrain from trying medical cannabis if other treatment has been inadequate. However, these results do suggest some improved monitoring may be advisable initially, especially in patients who are already at increased risk of cardiovascular disease.”

 

Researchers say this is the first nationwide study of its kind investigating the cardiovascular effects of medical cannabis for chronic pain. However, they caution that this is an observational study. Dr. Holt explained: “Despite our best efforts to make a balanced comparison, it can never be assumed that patients prescribed medical cannabis do not differ from patients not prescribed medical cannabis, and this could influence the results.”

 

He added: “We need much more research in this area. Before concluding anything, results from this study should be replicated in other countries and settings. It would also be interesting to understand if there are any links between long-term cannabis use and heart failure, stroke, or acute coronary syndrome. This would be an important area to clarify since chronic pain can persist for many years.”

 

In an accompanying editorial [2], Prof. Robert L. Page from the University of Colorado, USA, said: “Close pharmacovigilance of cannabis, as well as its safety and efficacy, have been limited by decades of worldwide illegality and by the ongoing classification of cannabis as a Schedule 1 controlled substance in the USA. Nonetheless, with increased cannabis decriminalisation and legalisation across the globe, the association between cannabis exposure and incident cardiovascular events has emerged as an important safety signal.

 

“Therapeutically, these findings suggest that medical cannabis may not be a ‘one-size-fits-all’ therapeutic option for certain medical conditions and should be contextualised based on patient comorbidities and potential vulnerability to side effects.

 

“Cannabis is typically referred to as recreational and ‘medical’ or ‘medicinal’. This latter terminology has come under scrutiny as it includes both phytochemical-derived cannabis products and also those prescription cannabinoids approved in the EU. Additionally, the term ‘medical’ implies that the product may have some clinical monitoring along with safety and efficacy data, which is far from true with cannabis. To this end, I would argue that ‘cannabis for therapeutic use’ would be a more appropriate terminology rather than ‘medical’.”

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JOURNAL

European Heart Journal

DOI

10.1093/eurheartj/ehad834 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

People

ARTICLE TITLE

Cannabis for chronic pain: cardiovascular safety in a nationwide Danish study

ARTICLE PUBLICATION DATE

11-Jan-2024

 

Need for speed: How hummingbirds switch mental gears in flight

Peer-Reviewed Publication

UNIVERSITY OF BRITISH COLUMBIA

 

IMAGE: 

UNIVERSITY OF BRITISH COLUMBIA ZOOLOGISTS FOUND HUMMINGBIRDS USED TWO DISTINCT STRATEGIES TO CONTROL HOVERING AND FORWARD FLIGHT.

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CREDIT: ANAND VARMA

Hummingbirds use two distinct sensory strategies to control their flight, depending on whether they’re hovering or in forward motion, according to new research by University of British Columbia (UBC) zoologists. 

“When in forward fight, hummingbirds rely on what we call an ‘internal forward model’—almost an ingrained, intuitive autopilot—to gauge speed,” says Dr. Vikram B. Baliga, lead author of a new study on hummingbird locomotion published in Proceedings of the Royal Society B. “There’s just too much information coming in to rely directly on every visual cue from your surroundings.” 

“But when hovering or dealing with cues that might require a change in altitude, we found they rely much more on real-time, direct visual feedback from their environment.”

The findings not only provide insights on how the tiny, agile birds perceive the world during transitions in flight, but could inform the programming of onboard navigation for next generation autonomous flying and hovering vehicles.

Hummingbird flight recorder

The researchers had hummingbirds perform repeated flights from a perch to a feeder in a four-metre tunnel. To test how the birds reacted to a variety of visual stimuli, the team projected patterns on the chamber’s front and side walls. Each flight was videoed.

In some scenarios, the researchers projected vertical stripes moving at various speeds on the side walls to mimic degrees of  forward motion. Sometimes, horizontal stripes on the side mimicked changes in altitude. On the front wall, the researchers projected rotating swirls, designed to create the illusion of a change in position.

“If the birds were taking their cues directly from visual stimuli, we’d expect them to adjust their forward velocity to the speed of vertical stripes on the side walls,” says Dr. Baliga. “But while the birds did change velocity or stop altogether depending on the patterns, there wasn’t a neat correlation.”

However, during flight, the hummingbirds did adjust more directly to stimuli indicating a change in altitude. And during hovering, the birds also worked to adjust their position much more closely to shifting spirals the research team projected on the front wall.

“Our experiments were designed to investigate how hummingbirds control flight speed,” says Dr. Doug Altshuler, senior author on the paper. “But because the hummingbirds took spontaneous breaks to hover during their flights, we uncovered these two distinct strategies to control different aspects of their trajectories.”

Hummingbird in tunnel [VIDEO] |

University of British Columbia zoologists observed how hummingbirds reacted to a variety of visual stimuli using a four-metre flight tunnel.

Testing tunnel [VIDEO] |

JOURNAL

Proceedings of the Royal Society B Biological Sciences

DOI

10.1098/rspb.2023.2155 

METHOD OF RESEARCH

Observational study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Hummingbirds use distinct control strategies for forward and hovering flight

ARTICLE PUBLICATION DATE

10-Jan-2024