The biology of death (Introduction)

by David Turell , Monday, August 22, 2016, 21:15 (3013 days ago)

Pronouncing someone dead is not difficult, from my standpoint as a physician. If a person is non responsive, not breathing and has no pulse they are dead. With resuscitation efforts they can at times be brought back with an intact brain if the efforts start within four minutes. However, if truly 'dead', that is, beyond resuscitation, the entire body is not dead as shown by the ability to harvest organs for transplant. Now it is shows that some genes may activate with death or stay active for many days after clinical whole body 'death':-https://www.newscientist.com/article/2094644-hundreds-of-genes-seen-sparking-to-life-two-days-after-death/-"Peter Noble and Alex Pozhitkov at the University of Washington, Seattle, and their colleagues investigated the activity of genes in the organs of mice and zebrafish immediately after death. They did this by measuring the amount of messenger RNA present. An increase in this mRNA - which genes use to tell cells to make products such as proteins - indicates that genes are more active.-"Noble's team measured mRNA levels in zebrafish, and in brain and liver samples from mice at regular intervals for up to four days after death. They then compared these with mRNA levels measured at the time of death.-"As you might expect, overall mRNA levels decreased over time. However, mRNA associated with 548 zebrafish genes and 515 mouse genes saw one or more peaks of activity after death. This meant there was sufficient energy and cellular function for some genes to be switched on and stay active long after the animal died.-"These genes cycled through peaks and dips in activity in a “non-winding down” manner, unlike the chaotic behaviour of the rest of the decaying DNA, says Noble.-"Hundreds of genes with different functions “woke up” immediately after death. These included fetal development genes that usually turn off after birth, as well as genes that have previously been associated with cancer. Their activity peaked about 24 hours after death.-***-"So why do so many genes wake up after death? It is possible that many of the genes become active as part of physiological processes that aid healing or resuscitation after severe injury. For example, after death, some cells might have enough energy to kick-start genes involved in the inflammation process to protect against damage - just as they would if the body were alive.-"Alternatively, a rapid decay of genes that normally suppress other genes - such as those involved in embryological development - might allow the usually quiet genes to become active for a short period of time.-***-"The research also raises important questions about our definition of death - normally accepted as the cessation of a heartbeat, brain activity and breathing. If genes can be active up to 48 hours after death, is the person technically still alive at that point? “Clearly, studying death will provide new information on the biology of life,” says Noble.-***-"What happens when we die? Well, that depends on where we end up. A body that has been refrigerated and encased in a coffin could take decades to completely decompose.-"But out in the open, the human body can disappear in just months. Here, within minutes of death, carbon dioxide starts to accumulate in our blood, causing cells to burst open and spew out enzymes that digest tissues. Within half an hour, blood starts to pool at the lowest point, while the rest of the body turns pale. Rigor mortis then sets in as calcium ions diffuse into cells causing muscles to contract.-"Three days later, putrification occurs as microbes that live in our gut break down proteins, creating a repulsive odour. They produce gases that bloat the body, which after two weeks collapses.-"Our flesh is rapidly consumed by bacteria and maggots. Eventually, after months or years, only bones are left - minus their collagen - which succumbs to bacteria and fungi."-Comment: This raises the issue in regard to NDE's whether some lower part of the brain can remain active in some undetected way to give the experiences reported?