Pondering resistance
Microwaving deltamethrin can renew the insecticide’s ability to kill mosquitoes that have become resistant to it. Scientists are trying to incorporate the new insecticide into bed nets. Tina Hesman Saey reported in “Restoring an insecticide’s mosquito-killing power” (SN: 6/17/23, p. 4).
Although the finding “sounds like a welcome discovery,” reader Linda Ferrazzara wrote, “might the newer, more effective version of the insecticide also have more serious adverse effects on the human beings it’s supposed to protect?”
Deltamethrin is so commonly used as an insecticide because it’s much more lethal for insects than it is for mammals, says Bart KahrCrystallographer at New York University. According to him, the lethal dosage for humans, which is based upon toxicology data of rats, is more than 100 billions times that for mosquitoes.
Because microwaving changes the crystal structure of deltamethrin but not its chemical makeup, it is unlikely that the lethal dosage would change. Kahr says. Although the new form may deliver deltamethrin more quickly to both humans as well as mosquitoes it would still require a prolonged exposure to high levels of insecticide for a mammal to experience any adverse effects. “Of course, no one has made such an experiment, but it stands to reason from the data that we have,” he says.
Understanding pain
Four people with chronic pain who had brain implants revealed a possible biomarker for the condition. The brain signal may one day be used to track the treatment response. Laura Sanders reported in “The brain is implanted with a device that tracks chronic pain.” (SN: 6/17/23, p. 10).
On social media, some readers wondered what this discovery could mean for other types or long-lasting pain. “Am SO hoping that this will one day be expanded to those of us who have [the autoimmune disorder lupus],” Twitter user @SusanFi84657717 wrote. Facebook user Wernell L.Hoped that this finding could be applied to the pain of grief.
The study provided researchers with a unique insight into neuropathic chronic pain. This type of pain is rooted within the nervous systems. Sanders says. According to the study, three people had neuropathic symptoms after a stroke and another person experienced phantom leg pain.
“So far, researchers don’t have this detailed view of other types of long-lasting pain,” Sanders says. Although the study was small, it did provide some useful hints. Scientists discovered patterns of brain activity that were shared by the four participants during times of high pain. Researchers also found brain activity patterns specific to each person.
“Figuring out the neural signals — both common and unique — that come with various sorts of chronic pain is the first step,” Sanders says. “The bigger goal is to interfere with those signals. Scientists are now testing whether brain stimulation can short-circuit these particular pain signals.”
Corrective action
“Ancient molecules linked to complex life” (SN: 7/15/23 & 7/29/23, p. 6The sentence () incorrectly stated that the oldest eukaryotics fossils date back to 800,000,000 years ago. The sentence should read that the oldest known fossils of steroid date back 800 million years. The oldest known fossils of eukaryotes actually date back to almost 3 billion years.
