Some viruses are more lethal for men than women, British researchers say
New research out of the University of London shows that some viruses are more likely to kill men than women. Here's why.
Some viruses are more likely to kill men than women. That's the finding from a 2016 study in the journal Nature Communications. Researchers from the University of London looked at how oral Human Papilloma Virus (HPV) infections were more likely to turn into terminal throat cancer in “Japanese men than women, while it is equally likely in Caribbean women and men," according to the study.
Viruses like HPV spread through replication, copying themselves inside a host body and passing those copies to new hosts via bodily fluids. Viruses do that in two ways: vertically, from mother to child via breastfeeding or live birth, or; horizontally, between sexual partners. Either transmission method makes the host sick, and “that's not something a pathogen particularly sets out to do," study co-author Vincent Jansen told New Scientist. “It's shooting itself in the foot." Meaning, if the host becomes too ill, their body may redirect all resources toward fighting the spread of the virus rather than simply passing it on.
That's not what a virus wants. So they find ways around it — namely, identifying and treating host bodies differently. “Females, but not males, provide an additional route of transmission," the study explains, noting that “women can pass infections to their children during pregnancy, birth and breastfeeding," in addition to horizontal transmission through sexual intercourse, study authors Jansen and Francisco Úbeda told New Scientist. By simulating the spread of the Human T-cell Lymphotropic Virus Type 1 (HTLV-1) via mathematical models for both men and women, the researchers saw the virus displaying “an evolutionary pressure" on women “to be less harmful to them," New Scientist reports. Here's how the study summarizes it:
Natural selection favours pathogens causing differential mortality in men and women when they are horizontally and vertically transmitted. In particular, pathogens are expected to evolve a degree of male virulence equal to that of pathogens in a population without vertical transmission and a degree of female virulence lower than that of pathogens in a population without vertical transmission.
Basically, if the host has an opportunity to spread a virus in more than one way, it's too valuable to attack full on.
An additional theory about the discrepancy of the spread is “because women breastfeed their babies more commonly and for longer in Japan — giving the virus more opportunity to enter another host" Jansen told New Scientist. Yet Sabra Klein of Johns Hopkins also told New Scientist that this assumption “ignore[s] other variables – such as ethnicity or culture – that could also be involved" in the virus' spread.
More importantly, as New Scientist reports, “The study emphasises the need to conduct clinical trials in both sexes, rather than predominantly in men as is often the case, says David Duneau, an evolutionary biologist at the University of Toulouse, France. “The parasites themselves are behaving differently in males and females, so we need to know what they do in both sexes. The researchers agree with that, writing “one of the reasons why a sex-specific treatment has not been implemented is that the causes of sex-differences in virulence are not well understood" in the study.
The researchers also aren't sure how the viruses know the sex of the host, but “there are all sorts of hormonal and other pathways that are slightly different between men and women," Jansen says. Once they figure that out, they they could treat viral infections in the future by tricking it. “We could try to make the virus think it's in a female body rather than a male body and therefore take a different course of action," Jansen told New Scientist.
The findings may prove to be helpful for the spread of other viruses, as HTLV-1 is far from the only one to kill men more often than women, according to New Scientist:
Men infected with tuberculosis are 1.5 times more likely to die than women; men infected with human papillomavirus are five times more likely to develop cancer than women; and men infected with Epstein-Barr virus are at least twice as likely to develop Hodgkin's lymphoma as women.
Upstreamism advocate Rishi Manchanda calls us to understand health not as a "personal responsibility" but a "common good."
- Upstreamism tasks health care professionals to combat unhealthy social and cultural influences that exist outside — or upstream — of medical facilities.
- Patients from low-income neighborhoods are most at risk of negative health impacts.
- Thankfully, health care professionals are not alone. Upstreamism is increasingly part of our cultural consciousness.
Researchers hope the technology will further our understanding of the brain, but lawmakers may not be ready for the ethical challenges.
- Researchers at the Yale School of Medicine successfully restored some functions to pig brains that had been dead for hours.
- They hope the technology will advance our understanding of the brain, potentially developing new treatments for debilitating diseases and disorders.
- The research raises many ethical questions and puts to the test our current understanding of death.
The image of an undead brain coming back to live again is the stuff of science fiction. Not just any science fiction, specifically B-grade sci fi. What instantly springs to mind is the black-and-white horrors of films like Fiend Without a Face. Bad acting. Plastic monstrosities. Visible strings. And a spinal cord that, for some reason, is also a tentacle?
But like any good science fiction, it's only a matter of time before some manner of it seeps into our reality. This week's Nature published the findings of researchers who managed to restore function to pigs' brains that were clinically dead. At least, what we once thought of as dead.
What's dead may never die, it seems
The researchers did not hail from House Greyjoy — "What is dead may never die" — but came largely from the Yale School of Medicine. They connected 32 pig brains to a system called BrainEx. BrainEx is an artificial perfusion system — that is, a system that takes over the functions normally regulated by the organ. Think a dialysis machine for the mind. The pigs had been killed four hours earlier at a U.S. Department of Agriculture slaughterhouse; their brains completely removed from the skulls.
BrainEx pumped an experiment solution into the brain that essentially mimic blood flow. It brought oxygen and nutrients to the tissues, giving brain cells the resources to begin many normal functions. The cells began consuming and metabolizing sugars. The brains' immune systems kicked in. Neuron samples could carry an electrical signal. Some brain cells even responded to drugs.
The researchers have managed to keep some brains alive for up to 36 hours, and currently do not know if BrainEx can have sustained the brains longer. "It is conceivable we are just preventing the inevitable, and the brain won't be able to recover," said Nenad Sestan, Yale neuroscientist and the lead researcher.
As a control, other brains received either a fake solution or no solution at all. None revived brain activity and deteriorated as normal.
The researchers hope the technology can enhance our ability to study the brain and its cellular functions. One of the main avenues of such studies would be brain disorders and diseases. This could point the way to developing new of treatments for the likes of brain injuries, Alzheimer's, Huntington's, and neurodegenerative conditions.
"This is an extraordinary and very promising breakthrough for neuroscience. It immediately offers a much better model for studying the human brain, which is extraordinarily important, given the vast amount of human suffering from diseases of the mind [and] brain," Nita Farahany, the bioethicists at the Duke University School of Law who wrote the study's commentary, told National Geographic.
An ethical gray matter
Before anyone gets an Island of Dr. Moreau vibe, it's worth noting that the brains did not approach neural activity anywhere near consciousness.
The BrainEx solution contained chemicals that prevented neurons from firing. To be extra cautious, the researchers also monitored the brains for any such activity and were prepared to administer an anesthetic should they have seen signs of consciousness.
Even so, the research signals a massive debate to come regarding medical ethics and our definition of death.
Most countries define death, clinically speaking, as the irreversible loss of brain or circulatory function. This definition was already at odds with some folk- and value-centric understandings, but where do we go if it becomes possible to reverse clinical death with artificial perfusion?
"This is wild," Jonathan Moreno, a bioethicist at the University of Pennsylvania, told the New York Times. "If ever there was an issue that merited big public deliberation on the ethics of science and medicine, this is one."
One possible consequence involves organ donations. Some European countries require emergency responders to use a process that preserves organs when they cannot resuscitate a person. They continue to pump blood throughout the body, but use a "thoracic aortic occlusion balloon" to prevent that blood from reaching the brain.
The system is already controversial because it raises concerns about what caused the patient's death. But what happens when brain death becomes readily reversible? Stuart Younger, a bioethicist at Case Western Reserve University, told Nature that if BrainEx were to become widely available, it could shrink the pool of eligible donors.
"There's a potential conflict here between the interests of potential donors — who might not even be donors — and people who are waiting for organs," he said.
It will be a while before such experiments go anywhere near human subjects. A more immediate ethical question relates to how such experiments harm animal subjects.
Ethical review boards evaluate research protocols and can reject any that causes undue pain, suffering, or distress. Since dead animals feel no pain, suffer no trauma, they are typically approved as subjects. But how do such boards make a judgement regarding the suffering of a "cellularly active" brain? The distress of a partially alive brain?
The dilemma is unprecedented.
Setting new boundaries
Another science fiction story that comes to mind when discussing this story is, of course, Frankenstein. As Farahany told National Geographic: "It is definitely has [sic] a good science-fiction element to it, and it is restoring cellular function where we previously thought impossible. But to have Frankenstein, you need some degree of consciousness, some 'there' there. [The researchers] did not recover any form of consciousness in this study, and it is still unclear if we ever could. But we are one step closer to that possibility."
She's right. The researchers undertook their research for the betterment of humanity, and we may one day reap some unimaginable medical benefits from it. The ethical questions, however, remain as unsettling as the stories they remind us of.
Can you make solar power work when the sun goes down? You can, and Dubai is about to run a city that way.
- A new concentrated solar plant is under construction in Dubai.
- When it opens next year, it will be the largest plant of its kind on Earth.
- Concentrated solar power solves the problem of how to store electricity in ways that solar pannels cannot.
Believe it or not, for a few decades, giving people "milk transfusions" was all the rage.
- Prior to the discovery of blood types in 1901, giving people blood transfusions was a risky procedure.
- In order to get around the need to transfuse others with blood, some doctors resorted to using a blood substitute: Milk.
- It went pretty much how you would expect it to.
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