'Near death' experience, a result of improved survival rates

Near death experience is the reported memory of all impressions during a special state of consciousness, such as out of body experience, pleasant feelings, seeing a tunnel, a light, deceased relatives or a life review.

Psychologists defined the near death experience as the time of clinical death where a patient is unconscious due to insufficient blood supply to the brain because inadequate blood circulation, breathing or both. In this situation, if resuscitation is not started within 5-10 minutes irreparable damage is done to the brain and the patient will die.

Some people report near death experience (NDE) after a life threatening crisis. A longitudinal study was conducted in Netherlands between 2001-2009 which included 344 cardiac arrest patients who were successfully resuscitated.

The study was conducted among two groups, one group of cardiac patients who had a cardiac arrest with a near death experience (62) or 18%, and in the other group of cardiac patients who did not have a near death experience. This research studied the medical, pharmacological and psychological experiences among the two groups. The occurrence of the near death experience was not associated with duration of cardiac arrest or unconsciousness, medication, or fear of death before cardiac arrest. Significantly, in this study, more patients who had a near death experience, especially deep experience, died with in 30 days after resuscitation.

The researchers did not know, why so few cardiac patients reported near death experience after resuscitation, but they thought it could be explained by the age of the patients, memory power and brain damage during the cardiac arrest some people who have survived a life threatening crisis report an extraordinary experience.

Near death experience occurs with increasing frequency because of improved survival rates resulting from modern techniques of resuscitation.

The content of near death experience and the effects on patients seem similar worldwide, across all cultures and times.

The subjective nature and absence of a frame of reference for this experience lead to individual, cultural, and religious factors determining the vocabulary used to describe and interpret the experience.

Near death experiences are reported in many circumstances:

* Cardiac arrest in myocardial infarction (clinical death)

* Shock due to loss of blood in child birth or due to surgeries

Shock due to electrocution, allergies (anaphylactic shock) or shock due to severe infections.

Attempted suicide, near drowning, serious traffic accidents, mountaining accidents or in shipwreck situations.

Such experiences are also reported by people with severe depression or without clear causes in fully concious people. Several theories on the origin of near death experience have been proposed. Some Psychologists think the experience is caused by changes in the brain, such as brain cells dying due to lack of oxygen and nutrients. Another theory is that the near death experience is due to changing state of conciousness, in which perception (feelings), cognitive functioning, emotion, and sense of identity, functioning independently from normal body waking conciousness or dissociation from the body.

Patients who have undergone (survived) a near dear death experience has transformational process in their lives so they do not have fear of death and they accept any subsequent eventualities in a very rational way.

Similar experiences to near-death can occur during the terminal phase of an illness, and are called death-bed wishes.

Good short-term memory seems to be essential for remembering near death experiences. Patients with memory defects after prolong resuscitation reported fewer experiences.

Similar to near death experience can be induced through electrical stimulation of some parts of the brain (temporal lobe and the hippo campus of the brain), with high carbondioxide in the blood, during training of fighter pilots (rapid acceleration when the brain does not have enough oxygen). And in drug addicts (specially with LSD & Ketamine). These induced experiences can consist of unconsciousness, out of body experience, and seeing of light flashes of recollection from the past.

These recollections, however, consist of fragmented and random memories unlike the panoramic life-review that occurs in near death experiences. Further, transformational processes with changing life insight and disappearance of fear of death are not reported after induced experiences.

The most important point to consider hear is that the clear conciousness outside one's body the person experiencing at the moment, when the brain no longer functions (flat EEG recording).

The same happens when there is cardiac arrest (flat ECG,) and when there is flat EEG (brain is not functioning).

Furthermore, blind people (blind from birth), describes similar out-of-body experience during cardiac arrest or when the brain is not functioning (flat ECG & EEG).

More research should be conducted to explain scientifically the phenomena of the near death experiences, It should be focused on specific elements such as out-of-body experience and transcendence.

Dr. R.A. Ranjith Perera

Scientists showcase how early human embryo acquires its shape

How is it that a disc-like cluster of cells transforms within the first month of pregnancy into an elongated embryo? This mechanism is a mystery that man has tried to unravel for millennia.

The first significant step towards understanding the issue was made nearly a century ago in experiments conducted by the German embryologists Hans Spemann and Hilde Mangold. The two used early newt embryos and identified a group of cells within them which, upon transplantation, formed a two-headed tadpole.

In trying to understand why this happened, they concluded that what occurred is that the transplanted cells organised the vicinity into which they were placed to form a typical embryonic shape. They therefore dubbed such cells "organizer" cells.

The new embryo possessed both its own organizers and the transplanted ones, both of which organized nearby cells to form a head structure.Recently, Israeli scientists from the Hebrew University of Jerusalem have managed to generate human organiser cells, using human embryonic stem cells. Based on the similarity that dominates the initial developmental processes of all vertebrates, the group raised the human cells in conditions which recapitulate those of early amphibian embryogenesis. Within two days, the human cells started expressing genes characteristic of the organizer cells.

To verify that these cells derived from human embryonic stem cells posses a true organising ability, the researchers repeated Spemann and Mangold's experiments.

Only this time, the human cells, rather than those of amphibians, were transplanted into frog embryos.

The midline of an amphibian embryo is marked by a neural tube - a tissue destined to form the embryo's central nervous system. To the group's astonishment, some of the frog embryos that were transplanted with the human cells possessed not one but two neural tubes. The second tube was composed from frog cells, proving that the injected human cells organized the cells in their vicinity to acquire a tubular shape.

Notes:

The research was conducted by Nadav Sharon, a graduate student under the supervision of Nissim Benvenisty, the Hebert Cohn Professor of Cancer Research at the Alexander Silberman Institute of Life Sciences at the Hebrew University, in collaboration with Abraham Fainsod, the Wolfson Family Professor of Genetics at the Hebrew University-Hadassah Medical School, and was published in a recent issue of the Stem Cells journal. Shape determination during human embryonic development is an extremely important process, at which any aberration might lead to miscarriage or the birth of a severely defected newborn.

The identification of the human organizer should allow better understanding of this process.

Furthermore, the ability of the human organiser cells to shape a frog neural tube may assist in forming human neural tubes in culture, from which neural cells could be obtained for transplantation into people with spinal damage, though much further research would be required to reach that stage.

Source: Jerry Barach The Hebrew University of Jerusalem.

Molecular basis for DNA breakage, new approach to cancer treatment

Scientists have identified the molecular basis for DNA breakage, a hallmark of cancer cells. The findings of this research have been published in the journal Molecular Cell.

The DNA encodes the entire genetic information required for building the proteins of the cell. Hence, DNA breaks disrupt the proteins and lead to changes in the cell function. These changes can lead to defects in the control of cellular proliferation resulting in cancer development.

Using cutting edge technologies, researchers Prof. Batsheva Kerem and doctoral student Efrat Ozeri-Galai, of the Alexander Silverman Institute of Life Sciences in the Faculty of Science were able to characterize for the first time the DNA regions which are the most sensitive regions to breakage in early stages of cancer development.

This is a breakthrough in our understanding of the effect of the DNA sequence and structure on its replication and stability.

"A hallmark of most human cancers is accumulation of damage in the DNA, which drives cancer development," says Prof. Kerem. "In the early stages of cancer development, the cells are forced to proliferate. In each cycle of proliferation the DNA is replicated to ensure that the daughter cells have a full DNA. However, in these early stages the conditions for DNA replication are perturbed, leading to DNA breaks, which occur specifically in regions defined as 'fragile sites'."

In this research Prof. Kerem and Ozeri-Galai used a sophisticated new methodology which enables the study of single DNA molecules, in order to study the basis for the specific sensitivity of the fragile sites.

The findings are highly important since they shed new light on the DNA features and on the regulation of DNA replication along the first regions that break in cancer development.

The results show that along the fragile region there are sites that slow the DNA replication and even stop it. In order to allow completion of the DNA replication the cells activate already under normal conditions mechanisms that are usually used under stress. As a result, under conditions of replication stress, such as in early cancer development stages, the cell has no more tools to overcome the stress, and the DNA breaks.

The results of this study reveal the molecular mechanism that promotes cancer development. Currently, different studies focus on the very early stages of cancer development aiming to identify the events leading to cancer on the one hand and on their inhibition, on the other.

The result of the current research identified for the first time DNA features that regulate DNA replication along the fragile sites, in early stages of cancer development.

In the future, these findings could lead to the development of new therapeutic approaches to restrain and/or treat cancer.

Source: Jerry Barach The Hebrew University of Jerusalem

Greater risk of relapse in patients using anti-depressants

Patients who use anti-depressants are much more likely to suffer relapses of major depression than those who use no medication at all, concludes a McMaster researcher.

In a paper that is likely to ignite new controversy in the hotly debated field of depression and medication, evolutionary psychologist Paul Andrews concludes that patients who have used anti-depressant medications can be nearly twice as susceptible to future episodes of major depression.

The meta-analysis suggests that people who have not been taking any medication are at a 25 per cent risk of relapse, compared to 42 per cent or higher for those who have taken and gone off an anti-depressant.

Andrews and his colleagues studied dozens of previously published studies to compare outcomes for patients who used anti-depressants compared to those who used placebos.

They analysed research on subjects who started on medications and were switched to placebos, subjects who were administered placebos throughout their treatment, and subjects who continued to take medication throughout their course of treatment. Andrews says anti-depressants interfere with the brain's natural self-regulation of serotonin and other neurotransmitters, and that the brain can overcorrect once medication is suspended, triggering new depression.

Though there are several forms of anti-depressants, all of them disturb the brain's natural regulatory mechanisms, which he compares to putting a weight on a spring.

The brain, like the spring, pushes back against the weight. Going off antidepressant drugs is like removing the weight from the spring, leaving the person at increased risk of depression when the brain, like the compressed spring, shoots out before retracting to its resting state.

"We found that the more these drugs affect serotonin and other neurotransmitters in your brain - and that's what they're supposed to do - the greater your risk of relapse once you stop taking them," Andrews says. "All these drugs do reduce symptoms, probably to some degree, in the short-term. The trick is what happens in the long term.

Our results suggest that when you try to go off the drugs, depression will bounce back. This can leave people stuck in a cycle where they need to keep taking anti-depressants to prevent a return of symptoms." Andrews believes depression may actually be a natural and beneficial - though painful - state in which the brain is working to cope with stress.

"There's a lot of debate about whether or not depression is truly a disorder, as most clinicians and the majority of the psychiatric establishment believe, or whether it's an evolved adaptation that does something useful," he says. Longitudinal studies cited in the paper show that more than 40 per cent of the population may experience major depression at some point in their lives.

Most depressive episodes are triggered by traumatic events such as the death of a loved one, the end of a relationship or the loss of a job.

Andrews says the brain may blunt other functions such as appetite, sex drive, sleep and social connectivity, to focus its effort on coping with the traumatic event. Just as the body uses fever to fight infection, he believes the brain may also be using depression to fight unusual stress. Not every case is the same, and severe cases can reach the point where they are clearly not beneficial, he emphasises.

Source: Wade Hemsworth McMaster University

Genes vital in preventing childhood leukaemia identified

Researchers have identified genes that may be important for preventing childhood leukaemia. Acute lymphoblastic leukaemia (ALL) is a cancer of the blood that occurs primarily in young children. It's frequently associated with mutations or chromosomal abnormalities that arise during embryonic or fetal development. Working with mice, researchers led by Rodney DeKoter identified two key genes that appear essential in the prevention of B cell ALL, the most common form of ALL in children. The study is published online in Blood, the Journal of the American Society of Haematology.

In the study, mice were generated with mutations in two genes called PU.1 and Spi-B. Mutation of either PU.1 or Spi-B individually had little effect. Unexpectedly, mutation of both genes resulted in 100% of the mice developing B cell ALL. Eighty percent of ALL cases in children are of the B cell type. The study found PU.1 and Spi-B have unanticipated functional redundancy as "tumor suppressor" genes that prevent leukaemia. "You can think of PU.1 and Spi-B proteins as brakes on a car. If the main brake (PU.1) fails, you still have the emergency brake (Spi-B). However, if both sets of brakes fail, the car speeds out of control," explains DeKoter, an associate professor in the Department of Microbiology & Immunology at Western's Schulich School of Medicine & Dentistry. "And uncontrolled cell division is an important cause of leukaemia."

PU.1 is an essential regulator in the development of the immune system, and mutations in this gene have been previously associated with human ALL. DeKoter hopes these studies will ultimately lead to improved, less toxic, therapies for childhood leukaemia. Currently, about 80% of ALL patients go into complete remission when treated with aggressive chemotherapy. DeKoter is also affiliated with the Centre for Human Immunology at Western and the Children's Health Research Institute. The lead author on the paper is Kristen Sokalski, a 2011 BMSc graduate with an honours specialization in Biochemistry of Infection & Immunity. Stephen Li and Marek Gruca, both MSc students supervised by DeKoter, and Ian Welch and Heather Cadieux-Pitre of Western's Veterinary Services also worked on the project.

Source: Kathy Wallis University of Western Ontario