Don't say that people are dead. The cancer cells that have been left on the corpse, even the living cells that scientists write off from the corpse, are not so easy to raise. When I first started to raise cancer cells, I didn't know what to use to cultivate cancer cells, and I didn't know how to make cancer cells continue to divide. Most of the cancer cells taken from patients die quickly, and those that are not dead no longer divide. Without living cancer cells in vitro, many cancer research and drug experiments cannot be carried out.
Until later, a lady named Harriet Lax suffered from cervical cancer. She took some cancer tissues from Johns Hopkins Hospital and gave them to a research institution. Maybe the researchers were lucky, maybe these cells were tough enough, and they survived. These cells are named Hella cells.
So far, Hella cells have created a biomaterial industry worth billions of dollars. Most biological experiments that use cells need to buy their cells. The total weight of Hella cells propagated in the laboratory exceeds 65,438+000 Empire State Buildings. In addition to the requirements of scientific consistency and convenient comparison, this also reflects from another aspect that it is not easy to make cancer cells survive and proliferate in vitro-it is not so easy to find a cancer cell that can be well fed.
Even if ready-made cells are cultured in the laboratory, they may die in various ways: warm, dead, cold, dead, all of which may die in the wrong serum. Therefore, cancer cells are very fragile without living human environment. When a patient dies, cancer cells will die soon.
This question is interesting. As a doctor, I'll answer your question.
All students who have raised cancer cells know that cancer cells are very fragile and need specific culture medium, specific temperature, carbon dioxide concentration, pH value and so on. They should be especially careful not to be contaminated by bacteria. If they are polluted, they will die soon. Generally speaking, cancer cells are very fragile in vitro and need very good conditions to survive. Because cancer cells are different from bacteria and viruses, bacteria and viruses, especially bacteria, can reproduce in vitro and survive for a very long time.
However, cancer cells can't. Cancer cells are derived from normal cell mutations and have no ability to survive independently. All nutrition comes from the maternal supply, that is, from human beings themselves.
If a cancer patient dies, the heart stops beating and the lungs stop breathing, all cells in the body, including cancer cells, will begin to die. After sudden death, the golden rescue time of the brain is only 4 minutes, that is to say, more than 4 minutes, the brain will cause irreversible damage. After death, normal cells can survive for a few minutes or even dozens of minutes.
Cancer cells are similar to normal cells. They can only use some residual nutrients. When they are all consumed, cancer cells will die. So people die, if there is no spark, cancer cells will not live long, that is, a few minutes or dozens of minutes, and will soon die.
How long can cancer cells survive in nature if they are not cremated after death? There seems to be no special research to discuss this problem, so it is impossible to give a clear conclusion at present.
However, some studies have tested how long some cells can survive after death, and we can deduce the possible answer to this question in this way.
Single cells of unicellular organisms and multicellular organisms
Cells are the basic unit of life.
Single-celled organisms such as bacteria can survive in a suitable natural environment for a long time, and can achieve "immortality" through self-replication.
However, single cells of multicellular organisms do not have this ability and cannot survive independently in the natural environment for a long time.
Some netizens talk about the artificial culture of "Haila" cervical cancer cells, which has nothing to do with this topic.
In the world, not only Hela cells, but also most animal cells can be successfully cultured in Petri dishes for medical research. However, artificial cultivation with strictly controlled conditions is different from natural survival.
The survival of cells in multicellular organisms depends on the organizational conditions provided by biological systems to maintain their survival, that is, cells can only survive if their tissues maintain life activities.
Once the living body dies, it loses the supply of oxygen and energy provided by the system, and the tissue will die within a certain period of time.
And the cells inside will die one by one.
Of course, different cells have different tolerance to hypoxia after tissue death, and their survival time is also different.
How long can cells survive after the death of organisms? Recently, there was a rumor circulating on the Internet, saying, "Why can people live for 48 hours after death, but people give up treatment?" .
This rumor is based on a paper published by the University of Washington on 20 17, entitled "Tracking the Dynamics of Gene Transcription in Living Bodies after Death".
What the article says is that the researchers tracked and detected the changes of mRNA transcripts of 1063 genes within 96 hours after the death of adult mice and zebrafish. The results showed that most of the increase of mRNA occurred within 0.5 hours, a few occurred 24 hours after death, and the longest even reached 48 hours.
We know that the transcription, translation and expression of DNA in biological cells are a part of life activities, and maintaining this process means that the cell is still alive and alive.
Therefore, this study by the University of Washington shows that some cells will continue to survive after the death of adult mice and zebrafish, and the longest survival period can reach 48 hours.
If this research can be transplanted into people, it can be said that some cells can survive for up to 2 days after death.
In 20 12, a study by the pasteur institute in France separated viable muscle stem cells from human and mouse corpses preserved for 17 days and 14 days, indicating that stem cells have stronger hypoxia tolerance.
After the death of cancer patients, how long can cancer cells survive in corpses preserved in the natural environment? Death and cardiac arrest mean that tissues lose blood and oxygen supply, and different types of cells live for different times according to their tolerance to hypoxia.
Generally speaking, the lower the metabolic rate, the lower the degree of differentiation, the higher the tolerance to hypoxia and the longer the survival time.
We know that human cancer cells are mutated from normal cell genes, which are characterized by losing control of growth and division and becoming infinitely proliferated.
Infinite division and proliferation means a huge demand for the most oxygen and nutrients, which means that cancer cells have the highest metabolic rate.
This high demand is reflected in histology that cancer tissue has richer blood vessel distribution and blood flow than other tissues.
This means that cancer cells have the worst tolerance to hypoxia and ischemia.
Once the organism dies, the blood and oxygen supply to the tissue is interrupted, and cancer cells will die faster than other cells.
For example, the research of former Washington University shows that most cells die within half an hour after the death of organisms, and the general cancer cells should belong to this largest category.
Therefore, we can draw the conclusion that:
After the death of a cancer patient, the survival time of cancer cells in the corpse will not exceed half an hour. Cell is the basic structure and functional unit of organism, while human cell is the basic functional unit of human body. Cells in human tissues divide, proliferate and die every day. These processes are not noticed by us. They are regulated by the precise mechanism of the human body, and generally there will be no major problems except normal metabolism.
Cancer cell is a canceration process derived from mutated normal cells, which generally changes from molecular level to cellular level and then to tissue level. Most carcinogens act on human cells, causing cell replication errors. When the carcinogenicity is strong enough or the body's immune function is weak, cancer cells will "take the opportunity" to start proliferation and division without being regulated by internal mechanisms.
Different from normal cells, cancer cells have two characteristics: unrestricted growth and metastasis, and the canceration of cells is also a process from quantitative change to qualitative change, which usually takes several years or decades to develop into tumors. Due to the continuous proliferation of cancer cells, the later cancer develops faster, and at the current medical level, only the cumulative number of cancer cells reaches 654.38+0 billion can be detected by instruments and equipment, so it is necessary to carry out daily life prevention and regular physical examination.
Although cancer cells sound creepy, as long as you maintain good living habits, there will generally be no major problems. Moreover, cell reproduction is spread through blood and lymphatic channels. Without these "soil" and "nutrition" sources, cancer cells will become quite fragile and die.
Therefore, the cancer patients asked by the subject will not survive for a long time if they are not cremated after death.
After cancer patients die, of course, cancer cells die together for the following two important reasons.
Warburg effect (Warburg effect)
As we all know, cancer cells can divide rapidly and uncontrollably, producing a large number of new tumor cells, and their uncontrolled division requires a lot of energy or glucose. Tumor cells produce energy in a very special way: healthy cells rely on mitochondria to completely oxidize glucose and release a lot of energy, while most tumor cells are powered by inefficient glycolysis, even when oxygen is sufficient. Most of glucose metabolized by cancer cells is excreted in the form of lactic acid. Therefore, many cancers will increase the body's demand for glucose, weaken the glucose supply of some organs and muscles such as liver, kidney, heart or lung, and lead to fatigue. Most cancer patients will feel tired.
Tumor vascularization
The human body provides nutrition for the cells of the whole body through blood circulation. In the process of tumor occurrence, tumor angiogenesis is an important mechanism and feature of tumor growth and spread. New blood vessels are generated from existing blood vessels to supply cancer growth. New blood vessels will support the growth of cancer and provide necessary nutrition for tumor areas.
Therefore, it can be said that cancer cells are also very sensitive to energy deficiency. After the death of cancer patients, the blood circulation stops, which means that the nutritional supply of cancer cells is completely interrupted, and cancer cells cannot get energy and naturally die together.
HeLa cells are cervical cancer cells of American woman henrietta lacks. Without her knowledge, her cells were distributed to various medical institutions for research. From 1950s to today, her cells are still alive and making contributions to scientific research.
The terrible thing about cancer is that it can proliferate indefinitely in the body, thus affecting the normal metabolism and growth of other tissues. Although cancer cells can be so rampant in the body, once they leave the body, they become very fragile.
Killing cancer cells in vivo may require expensive and advanced instruments and drugs, but killing cancer cells in vitro is easy. A little salt water, a few bacteria, lack of oxygen and heating can easily kill it.
Cancer cells need a strict laboratory culture environment in vitro and add a variety of cytokines to survive. After all, cancer cells are not foreign objects, but their proliferation is out of control because of gene mutation. Cell growth, development, proliferation, division, metabolism, apoptosis and death is a very complex system, which is regulated by various biological signals, and these complex signals are in dynamic balance.
Cancer cells are, after all, cells from the human body. Like normal human cells, they need to live in a relatively stable internal environment and need oxygen, nutrients and ATP for energy supply. Cancer cells still need to rely on the normal function of the human body to survive. Therefore, it has been studied for a long time to "starve" cancer cells by inhibiting angiogenesis of tumor tissues and sugar intake of cancer cells. However, cancer cells and the human body are an organic whole, and this can only be achieved by killing one thousand enemies and losing 800.
Is it meaningful to struggle with how long cancer cells will live all day? Can we focus on how to prevent cancer cells from dividing, that is, how to prevent cancer? This is the fundamental thing.
How long can cancer cells in cancer patients live without cremation?
In fact, although cancer cells are so rampant in the human body, it seems that neither chemotherapy nor radiotherapy can clean them up, nor can various targeted immunization methods help them. However, once you leave the human body, which is an environment with suitable temperature, abundant water and oxygen, and rich nutrition, cancer cells are very fragile and cannot continue to survive as quickly as other cells, let alone find a new host.
So seemingly powerful cancer cells are not invincible cockroaches. They can be abused because they are part of the human body and the result of pathological replication of normal cells. It is easy to understand that they are regarded as a part of the human body. The biggest difference between cancer cells and normal cells is that its growth and replication are not controlled by human beings. Its replication and growth need more nutrition, which leads to the lack of nutrition in other organs and tissues. Its continuous replication and growth will squeeze the position of other organs, while cancer cells run around with vascular lymph and form metastasis, so the functions of other organs are more and more damaged. Once the primary or metastatic organs fail to function normally, the human body will not be able to do this. This is why cancer cells are harmful. However, if there is not enough nutrition supply and proper temperature and humidity, cancer cells are actually very fragile, just like newborn calves in cattle farms, who like to be naughty, but they are not necessarily more vital than the cows that feed them.
When it comes to the survival of cancer cells in vitro, the most famous is Hela cells. A woman named Harriet Lax has cervical cancer. In Johns Hopkins Hospital, a part of cancer tissue was removed and handed over to a research institution for culture. These surviving cancer cells are named Hella cells.
So far, Hella cells have created a biomaterial industry worth billions of dollars. Most biological experiments using cancer cells need to buy their cells, and their culture volume is huge, and the culture conditions, including water, temperature and nutrition, are very harsh. Therefore, it is not easy for cancer cells to survive and proliferate in vitro.
To give a more popular example, it is a bit like the relationship between people who destroy the environment and the earth. Although people can bosse around the earth at will, all kinds of natural disasters are similar to various treatment methods, and these damages can only be stopped in a limited time, but if they don't take the initiative to stop this damage, the earth will not last long sooner or later, and then people will have nowhere to live.
Cancer is the product of excessive proliferation of normal cells in human body. There is not a saying that "if you live long enough, you will get cancer." So when life ends, cancer cells will naturally die. Cancer cells are not viruses, so they will not survive.
As a doctor and researcher, the first thing I tell you is that cancer cells are just a special type of cells, but just like ordinary cells, as long as there is no nutrient supply, that is, blood vessels do not supply blood, they will die. And in which organ, it will die with which organ.
The process by which body organs disappear at death. Death will not come at once. To be exact, every organ will die automatically. For example, after a person died of an acute heart attack, the doctor said, "This patient died." From the doctor's point of view, this statement is correct.
Although a person is dead, his body is still in the middle of life and death for a certain period of time (the technical term is "intermediate life"). Different somatic cells and organs die at different times. The more oxygen is needed, the faster the cell or organ will die completely.
How long can a cell or organ live? The professional field is controversial. After consulting the professional books of forensic medicine, the results are as follows: (1) after 3 minutes, brain cells die; Cardiac cells died after 15 minutes; After 35 minutes, the liver cells died. After 60 minutes, the lung cells died; After 90 ~ 120 minutes, renal cells died; Muscle cells die after 2 to 8 hours, and nails die after 20 hours. Sperm, cartilage and tooth cells have the longest survival time, up to 4 days.
Therefore, cancer cells in the brain die first, followed by heart, liver, lungs, kidneys and muscles. Other organs don't have many cancer cells.