Jul 28, 2021 08:30 PM
(This post was last modified: Jul 28, 2021 08:38 PM by C C.)
(prevention community) A reversible male contraceptive, targeted to the testes with magnets
https://www.acs.org/content/acs/en/press...gnets.html
RELEASE: Women have several choices for long-lasting, reversible contraceptives, but most options for men are either single-use, such as condoms, or difficult to reverse, like vasectomies. Now, in a step toward a safe, long-lasting and reversible male contraceptive, researchers reporting in ACS' Nano Letters have developed magnetic, biodegradable nanomaterials that reduced the likelihood of mice fathering pups for at least 30 days.
Elevated temperatures, which can be caused by wearing too-tight pants or underwear, can decrease sperm count in men. Some researchers have explored the more intense heating of nanomaterials injected into the testes as a form of male birth control. However, the injection can be painful, the heating can damage skin, and most nanomaterials tested so far are not biodegradable. Weihua Ding, Fei Sun and colleagues wanted to develop a safe, effective magnetic-thermal approach to male contraception that doesn't need to be injected directly into the testes.
The researchers tested two forms of iron oxide nanoparticles, which are biodegradable and can be guided and heated with magnetic fields, as male contraceptives. One type of nanoparticle was coated with polyethylene glycol (PEG) and the other with citric acid. Although the PEG-coated nanoparticles could be heated to higher temperatures, they were not as easily manipulated by magnets as the other ones. So the researchers injected repeated doses of citric acid-coated nanoparticles into the bloodstream of mice for 2 days, guided the nanomaterials to the testes with magnets, and then applied an alternating magnetic field to the area for 15 minutes.
The nanoparticles heated the testes to a temperature of 104 F, shrinking them and inhibiting spermatogenesis before gradual recovery 30 to 60 days after treatment. The mice couldn't father any pups 7 days after treatment, but they were back to fathering about 12 pups per pregnant female at day 60. The nanoparticles were non-toxic to cells and were gradually eliminated from the body, offering new possibilities for male contraception, the researchers say.
(marine life community) Plastic, the Trojan Horse
https://www.port.ac.uk/news-events-and-b...ojan-horse
RELEASE: A new study has found plastic accumulation in foods may be underestimated. There is also concern these microplastics will carry potentially harmful bacteria such as E. coli, which are commonly found in coastal waters, up the food chain.
Researchers from the University of Portsmouth tested a theory that microplastics covered in a layer of microbes, (called a biofilm) ) were more likely to be ingested by oysters than microplastics that were clean. Although the experiment was carried out on oysters under laboratory conditions, scientists believe similar results could be found in other edible marine species that also filter seawater for food.
Up until now, studies to test the impacts of microplastics on marine life have typically used clean, virgin microplastics. However, this is not representative of what happens to microplastics in the marine environment. Microbes readily colonise microplastics that enter the ocean. In this study, published in Science of the Total Environment, scientists compared the uptake rates of clean microplastics versus microplastics with an E.coli biofilm coating. The results were worrying -- oysters contained 10 times more microplastics when exposed to the biofilm coated beads. It is hypothesised that these coated MPs appeared to be more like food to the oysters, explaining their preferential ingestion over clean microplastics.
The scientists say the implications for the food chain are concerning. The ingestion of microplastics is not only bad for the oysters, but it affects human health too. The plastic does not break down in the marine animal and is consumed when we eat it.
Lead researcher, Dr Joanne Preston, Reader in Marine Ecology and Evolution at the University of Portsmouth, said: "What we've discovered is that microplastic really is the Trojan Horse of the marine world. We discovered that clean plastics had little impact on the oysters' respiration and feeding rates -- but did have an impact when you fed them the microplastic hidden in the biofilm. The oysters took in more and it affected their health. It is unsure exactly how much this could affect the food chain, but the likelihood is because the creatures are ingesting more plastic and potentially, disease causing organisms, this will ultimately have a negative effect on human health. We know microplastics can be the mechanism by which bacteria are concentrated in coastal waters and this shows that they are more readily taken up by shellfish, and can be transferred to humans or other marine life."
Dr Preston said: "We have successfully tested a hypothesis -- this opens the door for more research on environmentally relevant studies of the long term impacts of biofilm coated microplastics on a wider range of marine life. We also need to study the transfer of microbes up the food chain via plastics in much greater detail."
Professor Steve Fletcher, Director of the University's Revolution Plastics initiative, said: "The findings in this research give us further insight into the potential harm microplastics are having on the food chain. It demonstrates how we could be vastly underestimating the effect that microplastics currently have. It is clear that further study is urgently needed."
Paper highlights:
• Microplastic (MP) pollution and its impact on marine organisms is a major concern.
• Microplastics are readily colonised with a biofilm in the marine environment.
• Filter-feeder uptake of microbially-coated MP was 10× greater than virgin MP uptake.
• Metabolic impacts were observed in filter-feeders exposed to microbially-coated MPs.
• Studies using virgin MP can underestimate the uptake and impact on marine organisms.
https://www.acs.org/content/acs/en/press...gnets.html
RELEASE: Women have several choices for long-lasting, reversible contraceptives, but most options for men are either single-use, such as condoms, or difficult to reverse, like vasectomies. Now, in a step toward a safe, long-lasting and reversible male contraceptive, researchers reporting in ACS' Nano Letters have developed magnetic, biodegradable nanomaterials that reduced the likelihood of mice fathering pups for at least 30 days.
Elevated temperatures, which can be caused by wearing too-tight pants or underwear, can decrease sperm count in men. Some researchers have explored the more intense heating of nanomaterials injected into the testes as a form of male birth control. However, the injection can be painful, the heating can damage skin, and most nanomaterials tested so far are not biodegradable. Weihua Ding, Fei Sun and colleagues wanted to develop a safe, effective magnetic-thermal approach to male contraception that doesn't need to be injected directly into the testes.
The researchers tested two forms of iron oxide nanoparticles, which are biodegradable and can be guided and heated with magnetic fields, as male contraceptives. One type of nanoparticle was coated with polyethylene glycol (PEG) and the other with citric acid. Although the PEG-coated nanoparticles could be heated to higher temperatures, they were not as easily manipulated by magnets as the other ones. So the researchers injected repeated doses of citric acid-coated nanoparticles into the bloodstream of mice for 2 days, guided the nanomaterials to the testes with magnets, and then applied an alternating magnetic field to the area for 15 minutes.
The nanoparticles heated the testes to a temperature of 104 F, shrinking them and inhibiting spermatogenesis before gradual recovery 30 to 60 days after treatment. The mice couldn't father any pups 7 days after treatment, but they were back to fathering about 12 pups per pregnant female at day 60. The nanoparticles were non-toxic to cells and were gradually eliminated from the body, offering new possibilities for male contraception, the researchers say.
(marine life community) Plastic, the Trojan Horse
https://www.port.ac.uk/news-events-and-b...ojan-horse
RELEASE: A new study has found plastic accumulation in foods may be underestimated. There is also concern these microplastics will carry potentially harmful bacteria such as E. coli, which are commonly found in coastal waters, up the food chain.
Researchers from the University of Portsmouth tested a theory that microplastics covered in a layer of microbes, (called a biofilm) ) were more likely to be ingested by oysters than microplastics that were clean. Although the experiment was carried out on oysters under laboratory conditions, scientists believe similar results could be found in other edible marine species that also filter seawater for food.
Up until now, studies to test the impacts of microplastics on marine life have typically used clean, virgin microplastics. However, this is not representative of what happens to microplastics in the marine environment. Microbes readily colonise microplastics that enter the ocean. In this study, published in Science of the Total Environment, scientists compared the uptake rates of clean microplastics versus microplastics with an E.coli biofilm coating. The results were worrying -- oysters contained 10 times more microplastics when exposed to the biofilm coated beads. It is hypothesised that these coated MPs appeared to be more like food to the oysters, explaining their preferential ingestion over clean microplastics.
The scientists say the implications for the food chain are concerning. The ingestion of microplastics is not only bad for the oysters, but it affects human health too. The plastic does not break down in the marine animal and is consumed when we eat it.
Lead researcher, Dr Joanne Preston, Reader in Marine Ecology and Evolution at the University of Portsmouth, said: "What we've discovered is that microplastic really is the Trojan Horse of the marine world. We discovered that clean plastics had little impact on the oysters' respiration and feeding rates -- but did have an impact when you fed them the microplastic hidden in the biofilm. The oysters took in more and it affected their health. It is unsure exactly how much this could affect the food chain, but the likelihood is because the creatures are ingesting more plastic and potentially, disease causing organisms, this will ultimately have a negative effect on human health. We know microplastics can be the mechanism by which bacteria are concentrated in coastal waters and this shows that they are more readily taken up by shellfish, and can be transferred to humans or other marine life."
Dr Preston said: "We have successfully tested a hypothesis -- this opens the door for more research on environmentally relevant studies of the long term impacts of biofilm coated microplastics on a wider range of marine life. We also need to study the transfer of microbes up the food chain via plastics in much greater detail."
Professor Steve Fletcher, Director of the University's Revolution Plastics initiative, said: "The findings in this research give us further insight into the potential harm microplastics are having on the food chain. It demonstrates how we could be vastly underestimating the effect that microplastics currently have. It is clear that further study is urgently needed."
Paper highlights:
• Microplastic (MP) pollution and its impact on marine organisms is a major concern.
• Microplastics are readily colonised with a biofilm in the marine environment.
• Filter-feeder uptake of microbially-coated MP was 10× greater than virgin MP uptake.
• Metabolic impacts were observed in filter-feeders exposed to microbially-coated MPs.
• Studies using virgin MP can underestimate the uptake and impact on marine organisms.