Mar 25, 2020 06:23 PM
(This post was last modified: Mar 25, 2020 08:11 PM by C C.)
Study shows commonly used mouthwash could make saliva significantly more acidic
https://www.plymouth.ac.uk/news/study-sh...e-to-teeth
RELEASE: The first study looking at the effect of chlorhexidine mouthwash on the entire oral microbiome has found its use significantly increases the abundance of lactate-producing bacteria that lower saliva pH, and may increase the risk of tooth damage.
A team led by Dr Raul Bescos from the University of Plymouth’s Faculty of Health gave a placebo mouthwash to subjects for seven days, followed by seven days of a chlorhexidine mouthwash.
At the end of each period, the researchers carried out an analysis of the abundance and diversity of the bacteria in the mouth – the oral microbiome – as well as measuring pH, saliva buffering capacity (the ability to neutralise acids in the mouth), lactate, glucose, nitrate and nitrite concentrations.
The research, published in Scientific Reports today, found using chlorhexidine mouthwash over the seven days led to a greater abundance of species within the families of Firmicutes and Proteobacteria, and fewer Bacteroidetes, TM7 and Fusobacteria. This change was associated with an increase in acidity, seen in lower salivary pH and buffering capacity.
Overall, chlorhexidine was found to reduce microbial diversity in the mouth, although the authors cautioned more research was needed to determine if this reduction in diversity itself increased the risk of oral disease.
One of the primary roles of saliva is to maintain a neutral pH in the mouth, as acidity levels fluctuate as a result of eating and drinking. If saliva pH gets too low, damage can occur to the teeth and mucosa – tissue surrounding the teeth and on the inside of the mouth.
The research also confirmed findings from previous studies indicating that chlorhexidine disrupted the ability of oral bacteria to turn nitrate into nitrite, a key molecule for reducing blood pressure. Lower saliva and blood plasma nitrite concentrations were found after using chlorhexidine mouthwash, followed by a trend of increased systolic blood pressure. The findings supported earlier research led by the University that showed the blood pressure-lowering effect of exercise is significantly reduced when people rinse their mouths with antibacterial mouthwash rather than water.
• Dr Bescos said: “There is a surprising lack of knowledge and literature behind the use of these products. Chlorhexidine mouthwash is widely used but research has been limited to its effect on a small number of bacteria linked to particular oral diseases, and most has been carried out in vitro. “We believe this is the first study to look at the impact of 7-day use on the whole oral microbiome in human subjects.”
• Dr Zoe Brookes and Dr Louise Belfield, Lecturers in the Peninsula Dental School at the University of Plymouth, are co-authors of the study.
• Belfield said: “We have significantly underestimated the complexity of the oral microbiome and the importance of oral bacteria in the past. Traditionally the view has been that bacteria are bad and cause diseases. But we now know that the majority of bacteria – whether in the mouth or the gut – are essential for sustaining human health.”
• Dr Brookes added: “As dental clinicians, we need more information on how mouthwashes alter the balance of oral bacteria, so we can prescribe them correctly. This paper is an important first step in achieving this. “In the face of the recent COVID-19 outbreak many dentists are now using chlorhexidine as a pre-rinse before dental procedures. We urgently need more information on how it works on viruses”
The study was carried out by a team from the University of Plymouth’s Institute of Health and Community, Peninsula Dental School, Peninsula Medical School and School of Biological and Marine Sciences, along with colleagues from Bishop Grosseteste University and University of the West of Scotland.
Study indicates vaporized cannabis creates drug-seeking behavior
https://news.wsu.edu/2020/03/24/study-in...-behavior/
RELEASE: Rats with regular access to cannabis seek more of the substance and tend to show increased drug-seeking behavior when cannabis is absent. That’s according to a new study conducted by neuroscientists in Washington State University’s Integrative Physiology and Neuroscience unit.
The research, published in The Journal of Neuroscience, is the next step to better understand the cognitive and neural effects of cannabis use in humans. “It’s always difficult to establish reliable cannabis-seeking behavior using animal models. In this study we have a clear and reliable response for cannabis by utilizing the very first self-administration model involving on-demand delivery of whole-plant cannabis vapor,” said Ryan McLaughlin, professor in WSU’s Integrative Physiology and Neuroscience unit.
So, how do you give a rat the option to self-administer cannabis? Well, their curious nose, of course.
WSU researchers trained male Sprague Dawley rats to poke their nose into a small port within a Plexiglas chamber with constant air flow to automatically deliver discrete “puffs” of whole-plant cannabis vapor. The chambers are equipped with a spigot that delivers vapor, a cue light that illuminates during vapor delivery, an exhaust system for vapor evacuation, and two small nose poke ports, one of which activates a three-second puff of cannabis vapor.
Animals were able to administer puffs of whole-plant, tetrahydrocannabinol-rich (THC) cannabis vapor during daily one-hour sessions over the course of 21 days. Another group of rats received cannabidiol-rich (CBD) cannabis vapor, and a control group received vapor not containing any cannabinoids. “By the third day of the study, animals began to establish associations between their nose pokes and the cannabis vapor delivery,” McLaughlin said.
Animals exposed to THC-rich cannabis vapor administered more vapor deliveries than the other two study groups from day four to day 21, sometimes doubling the number of deliveries to each group. What was more shocking was when cannabis was taken away on day 22. “They would show a burst in responding,” McLaughlin said. “It went from 17 to 18 nose pokes up to 70 or 80 on average. They were trying to figure out why it wasn’t working.”
In addition, drug-paired cues also increased the animals’ response rates. For example, researchers found an increase in nose poke responses when the cue light was introduced following an extended absence of THC-rich vapor delivery. "It was similar to when you have someone who has stopped smoking cannabis for a while but then sees their pipe or their vape pen, immediately that cue makes them want to seek that drug again,” Tim Freels, post-doctoral researcher and first author on the paper, said.
The researchers found that food intake was higher, and activity was lower for the animals exposed to THC-rich vapor, yet they expended more energy and burned more calories than the other two groups. “They experienced a lot of the same effects people would experience,” Freels said. “And that is very important when you’re trying to validate a model and then extend it to a human population.”
Up until the use of this new self-administration model, it was difficult to compare previous cannabis research in animals with the human condition, as most animal-cannabis studies involved an injection of THC or synthetic cannabinoids rather than giving the animal the option to self-administer whole-plant cannabis vapor.
For the McLaughlin Lab, the next steps are to look at the long-term effects of cannabis vapor self-administration during sensitive developmental periods, such as pregnancy or adolescence.
“We urgently need more information on the effects of cannabis use on the developing brain, and this model will be important for identifying potential risks that can be relayed to human cannabis users,” McLaughlin said.
Man in China dies from hantavirus, over 1,000 cases reported
https://www.upi.com/Top_News/World-News/...585134878/
RELEASE: March 25 (UPI) -- A man in China has died after testing positive for the hantavirus, according to Chinese state media. Global Times reported the patient, a migrant worker from southwestern Yunnan Province, died while traveling on a chartered bus to Shandong Province for work on Monday.
There is more than one strain of hantavirus, some more harmful than others, according to the U.S. Centers for Disease Control and Prevention. There is no approved cure or vaccine against hantaviruses in the United States. An inoculation may be available in China.
The group of diseases is spread primarily among rodents, and from rodents to humans. Humans may become infected with hantaviruses through contact with rodent urine, saliva or feces. The fatality rate is 36 percent.
"New World" hantaviruses are known to cause hantavirus pulmonary syndrome, or HPS. Symptoms include fatigue, fever and muscle aches, followed by coughing and shortness of breath, according to the CDC and other health authorities. Human-to-human transmission is extremely rare. A case of person-to-person transmission was recorded in Argentina in 1996, according to the CDC.
Malaysian Chinese-language newspaper China Press reported Wednesday the patient with the surname Tian was traveling on a bus with 30 migrant workers. It is unclear whether they were also infected. When Tian developed a fever, emergency staff may have suspected a case of the novel coronavirus, according to the report.
Southern Metropolis Daily, a Chinese newspaper published in the city of Guangzhou, said Tian's home province of Yunnan has reported a total of 1,231 hantavirus cases from 2015 to 2019. China developed a vaccine against the virus 20 years ago, which may have lowered fatalities, according to reports. The hantavirus is named after the Hantan River in South Korea, where Lee Ho-wang, a South Korean scientist, first isolated the virus in 1976, according to South Korean news service News 1.
https://www.youtube-nocookie.com/embed/bTm94HwlfUQ
https://www.plymouth.ac.uk/news/study-sh...e-to-teeth
RELEASE: The first study looking at the effect of chlorhexidine mouthwash on the entire oral microbiome has found its use significantly increases the abundance of lactate-producing bacteria that lower saliva pH, and may increase the risk of tooth damage.
A team led by Dr Raul Bescos from the University of Plymouth’s Faculty of Health gave a placebo mouthwash to subjects for seven days, followed by seven days of a chlorhexidine mouthwash.
At the end of each period, the researchers carried out an analysis of the abundance and diversity of the bacteria in the mouth – the oral microbiome – as well as measuring pH, saliva buffering capacity (the ability to neutralise acids in the mouth), lactate, glucose, nitrate and nitrite concentrations.
The research, published in Scientific Reports today, found using chlorhexidine mouthwash over the seven days led to a greater abundance of species within the families of Firmicutes and Proteobacteria, and fewer Bacteroidetes, TM7 and Fusobacteria. This change was associated with an increase in acidity, seen in lower salivary pH and buffering capacity.
Overall, chlorhexidine was found to reduce microbial diversity in the mouth, although the authors cautioned more research was needed to determine if this reduction in diversity itself increased the risk of oral disease.
One of the primary roles of saliva is to maintain a neutral pH in the mouth, as acidity levels fluctuate as a result of eating and drinking. If saliva pH gets too low, damage can occur to the teeth and mucosa – tissue surrounding the teeth and on the inside of the mouth.
The research also confirmed findings from previous studies indicating that chlorhexidine disrupted the ability of oral bacteria to turn nitrate into nitrite, a key molecule for reducing blood pressure. Lower saliva and blood plasma nitrite concentrations were found after using chlorhexidine mouthwash, followed by a trend of increased systolic blood pressure. The findings supported earlier research led by the University that showed the blood pressure-lowering effect of exercise is significantly reduced when people rinse their mouths with antibacterial mouthwash rather than water.
• Dr Bescos said: “There is a surprising lack of knowledge and literature behind the use of these products. Chlorhexidine mouthwash is widely used but research has been limited to its effect on a small number of bacteria linked to particular oral diseases, and most has been carried out in vitro. “We believe this is the first study to look at the impact of 7-day use on the whole oral microbiome in human subjects.”
• Dr Zoe Brookes and Dr Louise Belfield, Lecturers in the Peninsula Dental School at the University of Plymouth, are co-authors of the study.
• Belfield said: “We have significantly underestimated the complexity of the oral microbiome and the importance of oral bacteria in the past. Traditionally the view has been that bacteria are bad and cause diseases. But we now know that the majority of bacteria – whether in the mouth or the gut – are essential for sustaining human health.”
• Dr Brookes added: “As dental clinicians, we need more information on how mouthwashes alter the balance of oral bacteria, so we can prescribe them correctly. This paper is an important first step in achieving this. “In the face of the recent COVID-19 outbreak many dentists are now using chlorhexidine as a pre-rinse before dental procedures. We urgently need more information on how it works on viruses”
The study was carried out by a team from the University of Plymouth’s Institute of Health and Community, Peninsula Dental School, Peninsula Medical School and School of Biological and Marine Sciences, along with colleagues from Bishop Grosseteste University and University of the West of Scotland.
Study indicates vaporized cannabis creates drug-seeking behavior
https://news.wsu.edu/2020/03/24/study-in...-behavior/
RELEASE: Rats with regular access to cannabis seek more of the substance and tend to show increased drug-seeking behavior when cannabis is absent. That’s according to a new study conducted by neuroscientists in Washington State University’s Integrative Physiology and Neuroscience unit.
The research, published in The Journal of Neuroscience, is the next step to better understand the cognitive and neural effects of cannabis use in humans. “It’s always difficult to establish reliable cannabis-seeking behavior using animal models. In this study we have a clear and reliable response for cannabis by utilizing the very first self-administration model involving on-demand delivery of whole-plant cannabis vapor,” said Ryan McLaughlin, professor in WSU’s Integrative Physiology and Neuroscience unit.
So, how do you give a rat the option to self-administer cannabis? Well, their curious nose, of course.
WSU researchers trained male Sprague Dawley rats to poke their nose into a small port within a Plexiglas chamber with constant air flow to automatically deliver discrete “puffs” of whole-plant cannabis vapor. The chambers are equipped with a spigot that delivers vapor, a cue light that illuminates during vapor delivery, an exhaust system for vapor evacuation, and two small nose poke ports, one of which activates a three-second puff of cannabis vapor.
Animals were able to administer puffs of whole-plant, tetrahydrocannabinol-rich (THC) cannabis vapor during daily one-hour sessions over the course of 21 days. Another group of rats received cannabidiol-rich (CBD) cannabis vapor, and a control group received vapor not containing any cannabinoids. “By the third day of the study, animals began to establish associations between their nose pokes and the cannabis vapor delivery,” McLaughlin said.
Animals exposed to THC-rich cannabis vapor administered more vapor deliveries than the other two study groups from day four to day 21, sometimes doubling the number of deliveries to each group. What was more shocking was when cannabis was taken away on day 22. “They would show a burst in responding,” McLaughlin said. “It went from 17 to 18 nose pokes up to 70 or 80 on average. They were trying to figure out why it wasn’t working.”
In addition, drug-paired cues also increased the animals’ response rates. For example, researchers found an increase in nose poke responses when the cue light was introduced following an extended absence of THC-rich vapor delivery. "It was similar to when you have someone who has stopped smoking cannabis for a while but then sees their pipe or their vape pen, immediately that cue makes them want to seek that drug again,” Tim Freels, post-doctoral researcher and first author on the paper, said.
The researchers found that food intake was higher, and activity was lower for the animals exposed to THC-rich vapor, yet they expended more energy and burned more calories than the other two groups. “They experienced a lot of the same effects people would experience,” Freels said. “And that is very important when you’re trying to validate a model and then extend it to a human population.”
Up until the use of this new self-administration model, it was difficult to compare previous cannabis research in animals with the human condition, as most animal-cannabis studies involved an injection of THC or synthetic cannabinoids rather than giving the animal the option to self-administer whole-plant cannabis vapor.
For the McLaughlin Lab, the next steps are to look at the long-term effects of cannabis vapor self-administration during sensitive developmental periods, such as pregnancy or adolescence.
“We urgently need more information on the effects of cannabis use on the developing brain, and this model will be important for identifying potential risks that can be relayed to human cannabis users,” McLaughlin said.
Man in China dies from hantavirus, over 1,000 cases reported
https://www.upi.com/Top_News/World-News/...585134878/
RELEASE: March 25 (UPI) -- A man in China has died after testing positive for the hantavirus, according to Chinese state media. Global Times reported the patient, a migrant worker from southwestern Yunnan Province, died while traveling on a chartered bus to Shandong Province for work on Monday.
There is more than one strain of hantavirus, some more harmful than others, according to the U.S. Centers for Disease Control and Prevention. There is no approved cure or vaccine against hantaviruses in the United States. An inoculation may be available in China.
The group of diseases is spread primarily among rodents, and from rodents to humans. Humans may become infected with hantaviruses through contact with rodent urine, saliva or feces. The fatality rate is 36 percent.
"New World" hantaviruses are known to cause hantavirus pulmonary syndrome, or HPS. Symptoms include fatigue, fever and muscle aches, followed by coughing and shortness of breath, according to the CDC and other health authorities. Human-to-human transmission is extremely rare. A case of person-to-person transmission was recorded in Argentina in 1996, according to the CDC.
Malaysian Chinese-language newspaper China Press reported Wednesday the patient with the surname Tian was traveling on a bus with 30 migrant workers. It is unclear whether they were also infected. When Tian developed a fever, emergency staff may have suspected a case of the novel coronavirus, according to the report.
Southern Metropolis Daily, a Chinese newspaper published in the city of Guangzhou, said Tian's home province of Yunnan has reported a total of 1,231 hantavirus cases from 2015 to 2019. China developed a vaccine against the virus 20 years ago, which may have lowered fatalities, according to reports. The hantavirus is named after the Hantan River in South Korea, where Lee Ho-wang, a South Korean scientist, first isolated the virus in 1976, according to South Korean news service News 1.