viernes, 26 de junio de 2009

One step closer to end HIV life cycle

In order for viruses to reproduce, they must infect a cell, this part we understand. But do we really know how the most devastating of all Viruses and the smartest one of all times really works?

Once i was told that in order to provide an accurate answer i need to understand the question, and of course the subject. The HIV Virus is the ultimate question of our time and we need to be able to understand it if we want to be able to eradicate this threat.

Viruses are not technically alive: they are sort of like a brain with no body. In order to make new viruses, they must hi-jack a cell, and use it to make new viruses. Just as your body is constantly making new skin cells, or new blood cells, each cell often makes new proteins in order to stay alive and to reproduce itself. Viruses hide their own DNA in the DNA of the cell, and then, when the cell tries to make new proteins, it accidentally makes new viruses as well. HIV mostly infects cells in the immune system.

Scientists have discovered that specific microRNAs (non-coding RNAs that interfere with gene expression) reduce HIV replication and infectivity in human T-cells. In particular, miR29 plays a key role in controlling the HIV life cycle. The study suggests that HIV may have co-opted this cellular defense mechanism to help the virus hide from the immune system and antiviral drugs.

Replication: Once HIV binds to a cell, it hides HIV DNA inside the cell’s DNA: this turns the cell into a sort of HIV factory.

The microRNA miR29 suppresses translation of the HIV-1 genome by transporting the HIV mRNA to processing-bodies (P-bodies), where they are stored or destroyed. This results in a reduction of viral replication and infectivity.

Infection: Several different kinds of cells have proteins on their surface that are called CD4 receptors. HIV searches for cells that have CD4 surface receptors, because this particular protein enables the virus to bind to the cell. Although HIV infects a variety of cells, its main target is the T4-lymphocyte (also called the “T-helper cell”), a kind of white blood cell that has lots of CD4 receptors. The T4-cell is responsible for warning your immune system that there are invaders in the system.

Scientis think the virus may use this mechanism to modulate its own life cycle, and we can use this to our advantage in developing new drugs for HIV Retroviral therapies greatly reduce viral load but cannot entirely eliminate it. This interaction between HIV and miR29 may contribute to that inability. Perhaps, by targeting miR29, we can force HIV into a more active state and improve our ability to eliminate it.

The team of Scientist managed to looked at miR29 expression levels in infected and uninfected cells and found that miR29 expression was enhanced by HIV-1 infection. Blocking the activity of miR29 with interfering RNA resulted in increased replication and infectivity of the virus. The scientists tested the association of miR29 and HIV-1 by mutating both miR29 and its target region on the HIV virus. When either was altered, miR29s suppression of HIV replication and infectivity was reduced or eliminated. In addition, the team suppressed P-bodies in the cells and noted a similar effect. This suggests that HIV may use miRNAs to become dormant and escape immune response.


miƩrcoles, 20 de mayo de 2009

Child abuse Causes Lifelong Changes To DNA Expression And Brain

A study led by researchers in Canada who analysed post mortem brain samples of suicide victims with a history of being abused in childhood found changes in DNA expression that were not present in suicide victims with no childhood abuse history or in people who died of other causes. The affected DNA was in a gene that regulates the way the brain controls the stress response.

The research was the work of scientists from the Douglas Mental Health University Institute and McGill University in Montreal, Quebec, and the Singapore Institute for Clinical Sciences and was published online on 22 February in Nature Neuroscience.

Previous studies have shown that child abuse or neglect changes the hormonal stress response and increases the risk of suicide in the victim. Animal studies show that maternal care can influence the expression of genes that control the stress response.

In this study the researchers looked at samples of the hippocampus from human suicide victims with a history of childhood abuse. The hippocampus is a region of the brain that plays a key role in regulating the stress response.

They found changes in expression of the NC3R1 gene that were not present in suicide victims with no history of being abused in childhood. The changes weren't present in people who had died of other causes either.

For the study the researchers used samples from 36 brains: 12 came from suicide victims who had been abused as children, 12 came from suicide victims who had no such history, and 12 came from people who had died of other causes (the controls).

The researchers found that the child abuse victims had different "epigenetic" markings in a part of the brain that influences the hypothalamic-pituitary-adrenal (HPA) function, a stress-response that increases suicide risk.

This finding builds on an earlier study published in May last year that showed how child abuse can leave "epigenetic" marks on DNA.

Epigenetics studies the way that DNA is expressed: that is when the code behaves in a way that is not exactly what the DNA program says. DNA itself, the fundamental code, is inherited from the person's biological parents and remains fixed through a person's lifetime.

But the genes in the DNA are coated with a layer of chemicals called DNA methylation. These chemicals influence how the DNA is interpreted and they can be affected by changes in the environment, especially in early life such as when the new embryo is made, in the womb, and then later in childhood.

Co-author Dr Gustavo Turecki, associate professor in the Department of Psychiatry at McGill University and who practices at the Douglas Mental Health University Institute, said:

"We know from clinical experience that a difficult childhood can have an impact on the course of a person's life."

"Now we are starting to understand the biological implications of such psychological abuse", added fellow co-investigator Moshe Szyf, a professor in the Department of Pharmacology and Therapeutics at McGill.

The interaction between environment and DNA plays a key role in our ability to resist and deal with stress and this affects the risk of suicide, said the researchers. Epigenetic marks are the product of DNA and environment.

The researchers found that different types of care from the mothers changed the hypothalamic-pituitary-adrenal (HPA) function in rats by altering the receptors in the brain. In earlier studies they showed that simple behaviours such as when mothers licked their baby rats in early life had a significant effect on epigentic markings on specific genes that affected behaviour throughout the offsprings' lives.

But they also found that these epigenetic marks can be changed in adulthood with treatments that change the DNA coating: the treatment is called DNA methylation and it reverses the change to the stress response.

The brain samples in this latest study came from the Quebec Suicide Brain Bank and the Canadian Institutes for Health Research and the National Institute of Child Health and Development in the US paid for the research.

lunes, 18 de mayo de 2009

Mandatory Paternity Tests Before Birth Certificates Issued

NASHVILLE, Tenn. - State Rep. G. A. Hardaway is backing a bill requiring a paternity test performed on all babies before their fathers' names are listed on birth certificates.

"They'll bring tears to your eyes," said the Memphis Democrat.

Hardaway said personal pleas for help in his district prompted him to sponsor what could be called the "paternity proposal" in the Tennessee Legislature.

His proposal would affect single adults as well as married couples.

"Well, at some point society has to weigh the rights of the parents against the rights of the child," he said. "And I think this is one of the basic inherent rights that should go with the child."

Right now, it costs $7 to get a copy of a birth certificate. The proposed legislation would add $165 to the cost.

It's not just the price of paternity testing that upsets some people.

"I do not support a paternity bill," said state Rep. Sherry Jones, a Nashville Democrat. "I think it's a real affront to women to say that every baby born has to have a paternity test."

Rebecca Kopp agrees. She recently finished filling out the birth certificate paperwork for her three-month-old son.

"I think it's offensive because I am married," Kopp said. "Even for women who aren't married, if they want to get a birth certificate, I think that that should be their right. I don't think they should have to prove who the father is."

Hardaway contends it's every child's right to know their father. He said it's a struggle he sees everyday.

"Just because we have adults who want to live a lie, lie to each other, the child shouldn't suffer," he said. "The emotional trauma that children go thru when they finally realize that they've been living a lie, it's unforgivable."

The bill is in committee. Hardaway said he is working to change some of the language to help it survive.

Right now, if a woman has been married for 300 days before their baby was born, the husband's name automatically goes on the birth certificate. If a woman is not married and wants the father's name on the paperwork, she has to get a paternity test and have it notarized before the father's name is listed.

miƩrcoles, 8 de abril de 2009

A Newer, Better Way to prevent Cervical Cancer

Cervical cancer is caused mostly when a woman is infected in her cervical area with the human papillomavirus. There is now a DNA test that will permit the identification and prevention of cervical cancer.

These days most women know that they should go to their doctor about once a year and have a test done, known as a pap smear, that is used to identify the possible onset of cervical cancer. This test should be d one every year from the moment she becomes sexually active, and it consists of smearing a biological sample from the woman's cervix onto a growth medium to see if there are any cancerous cells.

"Pap smears check for cell changes caused by the cancer, but it is not foolproof. That's why it's done every year because it can miss some cell changes, which it might pick up the next year.

There are many reports of Pap smears not detecting abnormal cells until it's too late and the cancer is advanced. The DNA test, on the other hand, tests for the actual virus, which makes it much more effective as a test for cervical cancer because we now know that all cervical cancer is caused by this virus." - 'Good Morning America' medical contributor Dr. Marie Savard

Cervical Cancer kills about 4,000 women a year in the US, however the incidence rate is much much higher.

The Bill and Melinda Gates Foundation funded an 8 year study that has categorically shown the greater effectiveness of this method.

lunes, 9 de marzo de 2009

Obama Ends Stem Cell Research Ban - Excerpts from CBS News

The US is apparently changing their stance on the polemic subject of Stem Cell Research. Till recently, Stem Cell Research has been highly restricted. Two proposals to ease on the bans were shot down by former president George W. Bush.

"President Obama ... is allowing federal taxpayer dollars to fund significantly broader research on embryonic stem cells because "medical miracles do not happen simply by accident," and promised his administration would make up for the ground lost under his predecessor." - CBS News

Obama has taken a more "science friendly" stance with his policies and declarations during his campaign, so it comes as little surprise that he is going ahead with his promise.

"Rather than furthering discovery, our government has forced what I believe is a false choice between sound science and moral values," Was the statement of Preseident Obama as released by the White House.

viernes, 6 de marzo de 2009

DNA Testing and the Supreme Court

The supreme court has taken an interesting case, from the northernmost state of Alaska. It's the case of William Osborne, convicted of assaulting a prostitute. Now you may be asking what is a closed rape case from Alaska doing in front of the Supreme court, well that's the interesting part. Osbourne claims DNA Testing is a constitutional right.

Osbourne is requesting a new DNA test on the evidence that he states would clear his name. The problem is that he is asking for this after pleading guilty, for a reduced sentence, and being sentenced.

"Forty-four states already permit convicts to demand DNA testing, though the states apply different requirements. Since 1989, 232 convicted felons have been exonerated because of DNA testing."

Most states in the US allow some type of access to DNA testing, and only 6 don't already have a system in place (Alaska being one of them).

Now the results given by the supreme court will mark a shift in the legislation of legal DNA tests for criminal cases. Where before it was underthe State's purview, now it would be enforced by federal law.

lunes, 16 de febrero de 2009

Proteins and Amino Acids as the Origins of life

Scientists have been trying to figure out how life started on earth for quite a while now. One of the more famous experiments and research was conducted by Stanley Miller, where he tried to recreate the atmosphere of pre-life earth, and see if amino acids or complex molecules would arise.

A recent review of the samples from one of his experiments shows that it may have worked much more than was previously believed!

Amino Acids are essencial molecules that help make life possible.

Stanley Miller had believed his experiment a failure mainly due to the fact that 50 years ago we didn't have the technology that we have today. Today Scientists can read our genetic information much more precisely, especially thanks to DNA Testing