Tuesday, April 2, 2013

TV Viewing Linked To Antisocial Behaviors In 5-Year Olds

Five year-olds who watch TV for 3 or more hours a day have an increasingly higher risk of developing antisocial behaviors, such as stealing or fighting, by the age of 7.

However, the likelihood of this behavior is very small, according to the experts, who also found that the amount of time spent playing computer/electronic games had no affect on behavior.

The finding came from a new study that was published in Archives of Disease in Childhood.

Although lengthened screen viewing time has been associated with diverse behavioral and emotional issues in kids, the majority of prior research has centered only on TV and has been conducted in the U.S.

A previous study demonstrated that excessive TV viewing during childhood is associated with a higher risk of criminal behavior later in life, while a different report revealed that children's muscular fitness decreases the more hours they spend in front of the television.

The experts in the new study set out to examine how kids between the ages of 5 and 7 were psychologically and socially affected by their time spent watching TV and playing electronic games.

A representative sample of more than 11,000 kids were involved in the investigation, they were registered in the Millennium Cohort Study, which has been observing the long-term well-being and development of children born in the UK between 2000 and 2002.

The children's mothers were given a validated Strengths and Difficulties (SDQ) questionnaire when the kids were 5 years old, and then again when they were 7. The survey's aim was to evaluate how well-adjusted the children were.

The SDQ consisted of five scales, which measured:
  • conduct problems
  • poor attention span/hyperactivity
  • hard time making friends
  • emotional symptoms
  • empathy and concern for others - pro-social behaviors
The mothers were also inquired about the amount of time their kids spent in front of the TV or playing computer games when they were 5 years old.

Results showed that nearly two thirds of the kids watched TV for between one and 3 hours each day when they were five. Fifteen percent watched television for over 3 hours each day, and less than 2% did not watch TV at all.

At that age, kids spend significantly less time playing computer games, with just 3% playing for three or more hours each day.

After adjusting for factors likely to influence the results, such as parenting and family dynamics, the authors found that watching TV for 3 or more hours each day was significantly linked to a very a small increased chance of antisocial behavior (conduct problems) between the ages of five and seven.

However, prolonged TV viewing was not associated with other challenges, including emotional issues or attention problems.

Time spent playing electronic games had no comparable influence on the kids' behavior. "Although this might reflect the fact that children spent less time playing games than they did watching TV," the researchers explained.

The experts said:

"The links between heavy screen time and mental health may be indirect, rather than direct, such as increased sedentary behavior, sleeping difficulties, and impaired language development, and that the child's own temperament may predict screen time habits."

The authors concluded:

"[The study] suggests that a cautionary approach to the heavy use of screen entertainment in young children is justifiable in terms of potential effects on wellbeing, particularly conduct problems, in addition to effects on physical health and academic progress shown elsewhere."
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Breath Test Reveals Gut Bacteria Linked To Obesity

A growing body of evidence is increasingly showing us that the microbes in our gut influence our metabolism in surprising ways. Now a new study from the US suggests that a breath test of the gases they give out may indicate how susceptible a person is to developing obesity.

In The Endocrine Society's Journal of Clinical Endocrinology & Metabolism 26 March online issue, researchers from the Cedars-Sinai Medical Center in Los Angeles report how people with high levels of both hydrogen and methane in their breath are more likely to have a higher body mass index (BMI) and a higher proportion of body fat.

They suggest the presence of certain bacteria in the gut causes it to extract more calories from food, adding to weight gain.

Lead author Ruchi Mathur, director of the Diabetes Outpatient Treatment and Education Center in the Division of Endocrinology at Cedars-Sinai, says in a statement:

"This is the first large-scale human study to show an association between gas production and body weight," adding that "this could prove to be another important factor in understanding one of the many causes of obesity."

Mathur and her colleagues tested the exhaled breath of 792 people and found four patterns: normal breath, or breath containing higher levels of methane, higher levels of hydrogen, or higher levels of both gases.

And the participants' whose breath had higher levels of both methane and hydrogen were the ones significantly more likely to have a higher BMI and higher proportions of body fat.

A gut bacterium called Methanobrevibacter smithii is responsible for most of the methane produced in the human gut.

Mathur says that usually bacteria like M. smithii are beneficial because they help extract energy and nutrients from food.

But if there is too much M. smithii, it alters the energy balance so as to make the person more likely to put on weight.

It does not do this directly, but by the effect it has on neighbouring bacteria, the researchers suggest.

M. smithii produces methane by scavenging hydrogen from other microrganisms. The researchers propose that this gives hydrogen- producing bacteria a boost, making them more efficient so as to extract more nutrients and calories from food. It is this, which eventually leads to weight gain, says Mathur.

Mathur is also working on another study that seeks to confirm the link between M. smithii, obesity and pre-diabetes. On that study the participants are given a dose of antibiotics to wipe out the bacterium so that researchers can compare how efficiently they digest food when they have the bacterium in their gut to when they do not.

Mathur says we are only "beginning to understand the incredibly complex communities that live inside of us".

"If we can understand how they affect our metabolism, we may be able to work with these microscopic communities to positively impact our health," she adds.

Several examples of the surprising ways gut bacteria influence the human body have emerged in recent years.

For instance, an animal study published in the Journal of Proteome Research in February 2012, suggests that gut bacteria may play a role in obesity by slowing down the activity of energy-burning brown fat.

And in a study published in February 2013, US scientists describe how gut bacteria form part of a complex system that maintains the body's blood pressure.
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Scientists Identify Genetic Causes For Prostate, Breast And Ovarian Cancer In Breakthrough Research

More than 80 genome regions that can raise a person's risk of developing prostate, breast and ovarian cancers, have been identified in a huge study led by scientists from the University of Cambridge and The Institute of Cancer Research, London.

Scientists say that the work, conducted through COGS (Collaborative Oncological Gene-Environment Study), will push forward our understanding of the biological causes of cancer. They warn, however, that the findings do not provide enough data to currently predict who will develop breast, prostate or ovarian cancers on the basis of genetics alone.

COGS is an EU-based consortium where more than 160 research groups from all over the world coordinate their work.

Coordinator of the COGS, Per Hall, said "People are already asking us, 'Shouldn't you genotype all people, to determine their individual risk for being diagnosed with these cancers?',... But it's too early."

COGS has released a batch of 13 papers in five journals this week, including: Nature Communications, Nature Genetics, PLOS Genetics, the American Journal of Human Genetic, and Human Molecular Genetics.

The study will lead to a deeper understanding of how these cancers develop, and hopefully new therapies and targeted screening, the authors explained.

Seeking out SNPs or "spelling mistakes"

The researchers were specifically looking for SNPs (single nucleotide polymorphisms) - genetic variations - that might be associated with a greater risk of developing cancer. Authors from the Karolinska Institute in Sweden, who were involved in the study, describe the SNPs as "genetic spelling mistakes" or "typos".

An SNP ("typo" or "spelling mistake") is a change of a nucleotide at a single base-pair location on DNA
SNPs are part of our natural heritage, genetic "typos" we inherit. How they affect a person depends on where on the DNA strand the genetic defect is found.

The scientists studied the DNA of more than 100,000 cancer patients and an additional 100,000 individuals from the general population. They discovered mutations that patients with ovarian, breast or prostate cancers had in common.

Each DNA alteration slightly increases the risk of cancer. However, people with many SNPs may have a nearly 30% higher risk of developing breast cancer and 50% higher risk of prostate cancer.

Targeting screening tests to those most at risk of developing cancer

Co-author, Professor Doug Easton, from the Centre for Cancer Genetic Epidemiology at the Department of Public Health and Primary Care and the Department of Oncology at the University of Cambridge, said:

"We're on the verge of being able to use our knowledge of these genetic variations to develop tests that could complement breast cancer screening and take us a step closer to having an effective prostate cancer screening program.

By looking for people who carry most of these variations we will be able to identify those who are at the greatest risk of getting these cancers and then targeting screening tests to these individuals."

Many of the SNPs the scientists discovered were located near areas of the genome that control gene behavior.

When these "control areas" are altered, the "brakes" that prevent cells from growing out of control stop working, resulting in metastasis (cancer spreading throughout the body) or out-of-control cancer cell growth.

The more we understand how these genes affect the emergence and progression of cancer, the more effective treatments and prevention programs will become.

Professor Paul Pharoah, from the Centre for Cancer Genetic Epidemiology at the Department of Public Health and Primary Care, the Cambridge Institute of Public Health (CIPH) and the Department of Oncology at the University of Cambridge, said:

"The identification of genetic variants that are associated with cancer risks will give us important insights into the basic biology of cancer that may lead to the development of new therapies or better ways to target existing therapies."

SNPs linked to Prostate, Breast and Ovarian Cancers

  • Prostate cancer - the scientists found 23 genetic variations associated with prostate cancer, bringing the total to 78. Sixteen of these variations are specifically linked to the more aggressive and fatal forms of the disease.

    Cancer and genetics - representational image
    This groundbreaking research potentially brings us a step closer to the development of saliva tests to assess cancer risk
    Scientists at the Institute of Cancer Research, London, explained that following these discoveries, it is now possible to identify the top 1% of males with the greatest risk of developing prostate cancer - these men are 4.7 times more likely to develop the disease compared to the rest of the population. These men would be screened and monitored closely so that if they develop the disease, it is caught early enough when treatment is much more effective.

    Dr Jyotsna Batra, a Genetics scientist with Queensland University of Technology's (QUT's) Institute of Health and Biomedical Innovation, Australia, explained that scientists can now explain 35% of the hereditary risk of prostate cancer by combining the effects of the 78 variations - but it also means we still have 65% to go. QUT's main contribution to the study was in the area of prostate cancer.

    The scientists suggest that 78 may be just the tip of the iceberg and that there might be over 2,000 such markers that influence a man's risk of developing the disease.

  • Ovarian cancer - the scientists found 11 SNPs associated with ovarian cancer. It will also become possible to identify high risk females so that they may be offered more regular and earlier screening and closer monitoring.

    The Moffitt Cancer Center, Florida, focused on regions of the genome that influence ovarian cancer risk. Moffitt's Director, Thomas A. Sellers, Ph.D., M.P.H., and 17 other co-authors explained that through large-scale analysis of over 18,000 women with ovarian cancer and over 26,000 healthy women, scientists are now much closer to understanding the inherited factors that contribute to this disease.

  • Breast cancer - 49 SNPs associated with breast cancer were identified, more than doubling the number previously identified with the disease.
Some of the SNPs are located in regions that are associated with other cancers. This means several cancers share the same underlying mechanisms that can cause disease.

Faults in BRCA genes

The researchers also sought SNPs that might influence how different cancers behave and which regions impact on cancer risk for patients with faults in the BRCA genes.

We know that women who carry the BRCA gene defects have a higher risk of developing both ovarian and breast cancers. However, it is still not possible to determine which of them will go on to develop the diseases.

The study found that:
  • 5% of the females who carry the BRCA1 fault as well as most of the genetic mutations linked to BRCA1 have a higher than 80% risk of developing breast cancer by the time they reach 80 years of age.

  • Females with the BRCA1 defects and few of these variants have a 50% chance of developing beast cancer.
What does this mean for women with defects in their BRCA genes? - it will soon be possible for genetic counselors to tell them what their risk is of developing ovarian or breast cancers. It will help determine who should have earlier and more regular screenings.

Dr Kerstin Meyer, Senior Research Associate at the Cancer Research UK Cambridge Institute and affiliated with the Department of Oncology at the University of Cambridge, said:

"Current research is identifying many variants in the genome that are associated with breast cancer. My work at the CRUK Cambridge Institute studies the mechanisms underlying these associations. We examine how variants function to regulate specific target genes and what these target genes are.

Although some well-known cancer genes have been identified as targets, for example the cell cycle regulator CCND1, we have found that its dysregulation leading to breast cancer risk confounds expectations. Through a better understanding of the biology of cancer risk we hope to find interventions and therapies."

Antonis Antoniou, Cancer Research UK Senior Cancer Research Fellow from the Department of Public Health and Primary Care at the University of Cambridge, said "Women with BRCA 1 or 2 faults are more likely to get breast or ovarian cancer but have to live with the uncertainty of whether they will actually develop the disease. Our research puts us on the verge of being able to give women a much more accurate picture of how likely they are to develop breast or ovarian cancer and would help to guide them about the most appropriate type and timing of prevention or monitoring options for them. We need to now see how it could work in the clinic."

In a series of Accompanying Papers, the scientists investigated the changes that affect the behavior of different types of breast cancers. They identified some SNPs that are only linked to ER-Negative breast cancers (ER = estrogen receptor). This suggests that ER-negative breast cancers develop in a unique way, a discovery that should lead us to new therapies.

Dr Alison Dunning, from the Department of Oncology at the University of Cambridge said "Once the SNPs were discovered, we next needed to begin working out their mode of action, how some of these genetic changes cause cancer. When we examined the numerous genetic changes in the TERT gene, for example, we discovered very little evidence that they cause cancer by altering the length of chromosome end-caps, telomeres - countering previously held beliefs about using telomere length to predict cancer risk.

These types of genetic discoveries that we made during this study give us a new, exciting understanding of cancer biology and will hopefully lead to new drug targets."
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Unusual Bird Flu Virus Kills Two Men In China

Two men have died in Shanghai after being infected with the H7N9 bird flu virus strain, one that has never affected humans before, Chinese health authorities reported.

The two patients were aged 87 and 27 years. The Xinhua News Agency reported that the younger man, surnamed Wu, became ill on February 19th, 2013 and died just over three weeks later on March 4th. The older man, surnamed Li, became sick on February 27th and died on March 10th.

The older patients' two sons became ill with flu and were hospitalized. The younger son, aged 55, developed severe pneumonia and died. The older son, aged 67, recovered and is no longer in hospital. Chinese health authorities say that neither son had the H7N9 virus.

A third patient, in Chuzhou in the eastern province of Anhui, also became infected with the H7N9 virus strain and became ill on March 10th. The woman, surnamed Han, aged 35, is reported to be in a critical condition in hospital in Nanjing, capital of Jiangsu Province.

Little is known about how H7N9 spreads among humans

Health experts in China say they do not know how the virus strain has spread. They are certain that the three infected people did not transmit H7N9 to each other. Tests on 88 close contacts of the three infected people found no abnormalities.

The National Health and Family Planning Commission (the Commission) in China says that the three patients started off with coughs and fever, which then developed to pneumonia with breathing difficulties.

Commission laboratories confirmed that all three were infected with H7N9, an avian influenza (bird flu) strain known to affect birds, but not humans.

The World Health Organization (WHO) says there is no vaccine to protect humans from H7N9 infection.

H7N9 does not appear to be highly human transmissible

The Commission emphasized that there is no evidence indicating that H7N9 is highly transmissible from human-to-human. However, it is not possible to draw any conclusions from just three cases.

The Chinese CDC (Center for Disease Control and Prevention) says that it has a team of experts studying the toxicity and human-infection potential of the virus.

Shanghai Daily quotes Jiang Qingwu, dean of Public Health School of Fudan University, as saying "So far, it is still an animal virus not a human virus".

Timothy O'Leary, of the World Health Organization, said in an interview with the Associated Press:

"There is apparently no evidence of human-to-human transmission, and transmission of the virus appears to be inefficient, therefore the risk to public health would appear to be low."

Health departments throughout China have been urged to step up supervision and monitoring of all cases involving flu symptoms, respiratory problems, and pneumonia.

People with fever, coughing, and breathing problems have been told to visit their doctors immediately.

What is bird flu (avian influenza)?

Avian influenza, also known as avian flu or bird flu, is a flu caused by viruses that infect birds and make them sick. It is an infectious disease of birds caused by influenza virus strains type A. Highly pathogenic avian influenza (HPAI) is the more aggressive one.

Avian influenza affects several types of birds, including farmed poultry. In December 2012, pigs in China were found to be infected with the bird flu virus.

Bird flu (avian flu) is the illness, which is caused by the avian influenza virus.

Avian influenza can be transmitted from wild birds to farmed livestock or pet birds, and the other way round. The infection spreads via the saliva, feces, nasal secretions and the feed of infected birds. Since December 2003, there have been many bird flu outbreaks, which have directly killed or caused the culling of millions of farmed poultry and wild birds in Europe, Asia and Africa.

Scientists have identified over 16 different bird flu types. The one that causes the most concern is the H5N1 strain, because it can make humans very ill, and even kill them. Fortunately, H5N1 does not infect humans easily. However, some highly virulent strains have caused severe respiratory diseases in humans.

In the vast majority of human infections, the person was in contact with infected birds or surfaces/objects contaminated with their secretions or feces.

H5N1 kills 60% of humans who become ill after being infected. According to WHO, so far during this millennium H5N1 has killed 359 humans in twelve countries.

Experts worry that an avian influenza virus may one day mutate and become easily human-transmissible.

Scientists reported in the journal mBio last year that a new bird flu virus had infected harbor seals and could pose a threat to human health as well as wildlife
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Sleep Apnea In Kids Linked To Behavioral Problems

Obstructive sleep apnea, a common type of sleep-disordered breathing (SDB), has been linked to elevated rates of ADHD-like behavioral issues in kids, in addition to learning and adaptive problems.

The findings were published in the journal Sleep and came about after a five-year study which analyzed data from a longitudinal cohort called the Tucson Children's Assessment of Sleep Apnea Study (TuCASA).

The study assessed Caucasian and Hispanic kids ranging in age from 6 to 11 years to measure the incidence and prevalence of SDB and its consequences on neurobehavioral functioning.

Michelle Perfect, PhD, the study's lead author and assistant professor in the school psychology program in the department of disability and psychoeducational studies at the University of Arizona in Tucson, said:

"This study provides some helpful information for medical professionals consulting with parents about treatment options for children with SDB that, although it may remit, there are considerable behavioral risks associated with continued SDB. School personnel should also consider the possibility that SDB contributes to difficulties with hyperactivity, learning and behavioral and emotional deregulation in the classroom."

The study consisted of 263 kids who participated in a sleep study and a neurobehavioral test of assessments which included youth and parent-documented rating scales.

The outcomes revealed that 23 kids had incident sleep apnea that developed during the trial period, while 21 kids had persistent sleep apnea for the entire length of the study. An additional 41 children who started out with sleep apnea stopped having breathing issues during sleep when examined at the five-year follow-up.

In children with incident sleep apnea, the risk of having behavioral issues was four to five times higher. In kids with persistent sleep apnea, that risk was six times higher.

Compared with children who never experienced SDB, those with sleep apnea were more inclined to have parent-documented issues in the areas of:
  • attention
  • disruptive behaviors
  • hyperactivity
  • social competency
  • self-care
  • communication
Kids with persistent sleep apnea were shown to be seven times more likely to have parent-documented learning issues and three times more likely to earn grades of C or under.

Research reported at the 24th annual meeting of the Associated Professional Sleep Societies in 2010, revealed that the academic grades of children with sleep apnea are worse than students who do not have sleep-related breathing problems.

The authors noted that this was the first sleep-related study to utilize a standardized survey to measure adaptive functioning in normal youths with and without SDB.

Perfect concluded, "Even though SDB appears to decline into adolescence, taking a wait and see approach is risky and families and clinicians alike should identify potential treatments."

Sleep apnea is prevalent in approximately two percent of healthy children, according to the American Academy of Sleep Medicine. Sleep apnea in kids of this age is generally due to oversized tonsils and adenoids. Most of these children with sleep apnea also experience loud snoring.

Treatment choices include the removal of the adenoids or tonsils via surgery and the use of continuous positive airway pressure therapy (CPAP).
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Teen Challenges: Social Competence, Peer Acceptance And Autonomy, Negotiating Negative Peer Influences

Teenagers' struggles to connect with their peers in the early adolescent years while not getting swept along by negative peer influences predict their capacity to form strong friendships and avoid serious problems even ten years later. Those are the conclusions of a new longitudinal study by researchers at the University of Virginia that appears in the journal Child Development.

"Overall, we found that teens face a high-wire act with their peers," explains Joseph P. Allen, Hugh P. Kelly Distinguished Professor at the University of Virginia, who led the study. "They need to establish strong, positive connections with them while at the same time establishing independence in resisting deviant peer influences. Those who don't manage this have significant problems as much as a decade later."

Researchers followed about 150 teens over a 10-year period (starting at age 13 and continuing to 23) to learn about the long-term effects of their peer struggles early in adolescence. They gathered information from multiple sources - the teens themselves, their parents and peers, and by observing teens' later interactions with romantic partners. The teens comprised a racially, ethnically, and socioeconomically diverse group.

Teens who had trouble connecting well with their peers in early adolescence had difficulty establishing close friendships in young adulthood. Teens who didn't connect well at 13 also had more difficulty managing disagreements in romantic relationships as adults.

Teens who had trouble establishing some autonomy and independence with peers (especially with respect to minor forms of deviance such as shoplifting and vandalism) were found to be at higher risk for problems with alcohol and substance use, and for illegal behavior, almost a decade later.

Conversely, teens who were seen as desirable companions - those deemed empathetic, able to see things from different perspectives and control their impulses, and having a good sense of humor - were more likely to have positive relationships in young adulthood.

Teens who were able to establish some autonomy vis a vis peers' influences were more likely to avoid problematic behavior in young adulthood, with teens who showed they were able to think for themselves in the face of negative peer influences using less alcohol as early adults and having fewer problems with alcohol and substance abuse as young adults. But teens who were seen as desirable companions were more likely to have higher levels of alcohol use in early adulthood and future problems associated with alcohol and substance use.

"The findings make it clear that establishing social competence in adolescence and early adulthood is not a straightforward process, but involves negotiating challenging and at times conflicting goals between peer acceptance and autonomy with regard to negative peer influences," Allen notes.

"Teaching teens how to stand up for themselves in ways that preserve and deepen relationships - to become their own persons while still connecting to others - is a core task of social development that parents, teachers, and others can all work to promote," adds Allen.

Teens who managed both of these goals simultaneously - connecting with peers while retaining their autonomy - were rated by their parents as being most competent overall by age 23. "There is a positive pathway through the peer jungle of early adolescence," says Allen, "but it is a tricky one for many teens to find and traverse."
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Scientists Get Inside Look At How AIDS Virus Grooms Its Assault Team

A new study by Los Alamos National Laboratory and University of Pennsylvania scientists defines previously unknown properties of transmitted HIV-1, the virus that causes AIDS. The viruses that successfully pass from a chronically infected person to a new individual are both remarkably resistant to a powerful initial human immune-response mechanism, and they are blanketed in a greater amount of envelope protein that helps them access and enter host cells.

These findings will help inform vaccine design and interpretation of vaccine trials, and provide new insights into the basic biology of viral/host dynamics of infection.

During the course of each AIDS infection, the HIV-1 virus evolves within the infected person to escape the host's natural immune response and adapt to the local environment within the infected individual. Because HIV evolves so rapidly and so extensively, each person acquires and harbors a complex, very diverse set of viruses that develops over the years of their infection. Yet when HIV is transmitted to a new person from their partner, typically only a single virus from the diverse set in the partner is transmitted to establish the new infection.

The key discoveries here are the specific features that distinguish those specific viruses which successfully move to the new host, compared with the myriad forms in the viral population present in a chronically infected individual.

"The viruses that make it through transmission barriers to infect a new person are particularly infectious and resilient," said Los Alamos National Laboratory scientist Bette Korber. "Through this study we now better understand the biology that defines that resilience."

The team set out to determine whether the viruses that were successfully transmitted to a new patient might share distinct biological properties relative to those typically isolated from people with long-term, chronic infection. To do this, the group at U Penn cloned a set of intact viruses from acute infection, and a set of viruses from chronically infected people, and characterized them by measuring quantities that might be related to the virus's ability to successfully establish a new infection. They discovered several clear correlations. For example, transmitted viruses were both more infectious and contained more protective "envelope" per virus; envelope is the protein the virus uses to enter host cells.

The team identified an additional interesting property that could be a general characteristic of new viral infections: the transmitted HIV was capable of replicating and growing well in the presence of alpha interferon. Alpha interferon production is part of our innate human immune response to a new infection. As soon as a new viral infection is initiated in our bodies, local immune cells at the site of infection start secreting molecules called cytokines that have general antiviral activity and can inhibit the production of the newly infected virus. Alpha interferon is one of these potent cytokines.

In the early days of an HIV infection, this innate immune response increases to an intense level, called a "cytokine storm," which gradually recedes during infection. For a newly transmitted HIV to successfully establish infection, it must grow and expand in the new host while facing this cytokine storm. Although typical chronic viruses are sensitive to and inhibited by alpha interferon, transmitted HIV-1 viruses grew well in the presence of interferon.
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