Synthetic nucleotides injected into monkeys can block the replication of Ebola and Marburg viruses, suggesting it eventually may be possible to protect humans against these deadly bioterrorism agents, researchers said Sunday.
The monkeys get very sick, but most of them survive. The agents, called morpholino oligomers, are the first drugs approved by the Food and Drug Administration to go into clinical trials against the viruses — although those trials will, at least initially, be conducted in primates, not humans.
The results are “a potentially important proof of concept but still a long way from a product that can be used with confidence against human infections,” said virologist Alan L. Schmaljohn of the University of Maryland School of Medicine, who was not involved in the research.
Schmaljohn cautioned that the drugs were given within an hour after infection and that they could be much less effective later in the course of the disease or against a more aggressive strain of the viruses.
Genes reside along long chains of DNA called chromosomes. c have found that a variation in a gene on the sex chromosome X may enhance an immune response that leads to lupus in men.
Systemic lupus erythematosus (SLE) is an autoimmune disease that predominantly affects women. Interestingly, researchers found that although the variation occurred in a gene on the X, or female, chromosome, its influence was stronger in men than in women. Humans hold two sex chromosomes — men have an X and Y, while women have two Xs. Previous studies have shown that genetic variations on the X chromosome contribute to the development of lupus.
In this study, Betty P. Tsao, Ph.D., a professor of medicine in the Division of Rheumatology at the David Geffen School of Medicine at UCLA, and colleagues found that certain common variations of DNA sequences within a specific X-linked gene triggered a stronger response in the immune system, increasing the risk of developing lupus, especially in men.
This study was part of an international effort to study the genetics of lupus in broader ethnic groups. Researchers genotyped 9,274 Eastern Asians individuals, including those with lupus and healthy controls. The stronger genetic effects were seen in men, compared with women, and especially in Chinese and Japanese men. Further study will look at other ethnicities.
Researchers say the finding will lead to greater understanding of the development of lupus and to further exploration of the sex-specific genetic contributions of the disease, which could result in more targeted therapies.
The study was funded by the Lupus Research Institute, a nonprofit association dedicated to supporting innovative research in lupus.
Researchers from The Wistar Institute recently reported that a human adenovirus called AdHu26, once thought uncommon, is not so rare after all. This could be bad news for scientists eager to use engineered AdHu26 human adenoviruses as vaccines against HIV and other diseases. In this approach, adenoviruses, which commonly cause respiratory-tract infections, are rendered relatively harmless before being used as vectors to deliver genes from pathogens, which then stimulate the body to generate an immune response. Yet studies show that a viral vector may be less effective if the vector is based on a type common in a population, because humans will have previously developed immunity to it.
“AdHu26 is considered by some to be rare in nature and thus there should be less pre-existing immunity. Dr. Hildegund Ertl [at Wistar] is claiming this is incorrect at least for certain human populations,” says Mark J. Newman, Ph.D., Vice President of Research and Development at GeoVax Labs, headquartered in Smyrna, Georgia. In its quest for an HIV vaccine, GeoVax has turned for help to a poxvirus vector called Modified Vaccinia Ankara (MVA), originally developed as a safer smallpox vaccine.
“Since we no longer administer smallpox vaccine except to the military and a select group of first responders for the potential use of smallpox by bioterrorists and smallpox has been eliminated from the human population, the vast majority of people are not being exposed to vaccinia viruses, of which MVA is one,” continues Dr. Newman. “Thus there is a lack of pre-existing immunity, at least in people who were born after 1971 when the universal use of the smallpox vaccine was discontinued.”
Because of the difficulty raising antibodies that are capable of totally blocking natural HIV infections, the GeoVax vaccine approach has focused on raising cellular immune responses in addition to antibodies, which together should be better able to block and control the infections than either can alone. The company’s vaccine proteins, which are inactivated proteins from HIV, are expressed in cells of the vaccinated person following administration of genetically engineered DNA vectored vaccines and live viral vector MVA vaccines.
The most robust statistical examination to date of our species’ genetic links to “mitochondrial Eve” – the maternal ancestor of all living humans – confirms that she lived about 200,000 years ago.
The Rice University study was based on a side-by-side comparison of 10 human genetic models that each aim to determine when Eve lived using a very different set of assumptions about the way humans migrated, expanded and spread across Earth.
The research is available online in the journal Theoretical Population Biology.
The quest to date mitochondrial Eve (mtEve) is an example of the way scientists probe the genetic past to learn more about mutation, selection and other genetic processes that play key roles in disease.
For example, the way scientists attempt to date mtEve relies on modern genetic techniques. Genetic profiles of random blood donors are compared, and based upon the likenesses and differences between particular genes, scientists can assign a number that describes the degree to which any two donors are related to one another.
Using mitochondrial genomes to gauge relatedness is a way for geneticists to simplify the task of finding common ancestors that lived long ago. That is because the entire human genome contains more than 20,000 genes, and comparing the differences among so many genes for distant relatives is problematic, even with today’s largest and fastest supercomputers.
But mitochondria – the tiny organelles that serve as energy factories inside all human cells – have their own genome. Besides containing 37 genes that rarely change, they contain a “hypervariable” region, which changes fast enough to provide a molecular clock calibrated to times comparable to the age of modern humanity.
Because each person’s mitochondrial genome is inherited from his or her mother, all mitochondrial lineages are maternal.
To infer mtEve’s age, scientists must convert the measures of relatedness between random blood donors into a measure of time.
“You have to translate the differences between gene sequences into how they evolved in time,” said co-author Krzysztof Cyran, vice head of the Institute of Informatics at Silesian University of Technology in Gliwice, Poland.
Within each model, the answers to these questions take the form of coefficients – numeric constants that are plugged into the equation that returns the answer for when mtEve lived.
Each model has its own assumptions, and each assumption has mathematical implications. To further complicate matters, some of the assumptions are not valid for human populations. For example, some models assume that population size never changes.
That is not true for humans, whose population has grown exponentially for at least several thousand generations. Other models assume perfect mixing of genes, meaning that any two humans anywhere in the world have an equal chance of producing offspring.
Cyran said human genetic models have become more complex over the past couple of decades as theorists have tried to correct for invalid assumptions. But some of the corrections – like adding branching processes that attempt to capture the dynamics of population growth in early human migrations – are extremely complex.
Which raises the question of whether less complex models might do equally well in capturing what’s occurring.
Buenos Aires – Argentine researchers have found that radiation emitted by an Internet-connected computer resting on the user’s legs may affect male fertility by reducing sperm motility and fragmenting DNA.
The research, first in the world on the subject, was carried out by experts from Nascentis, a reproductive medicine center located in Córdoba, Argentina. The results of the study will be presented at the 66 Congress of the American Society for Reproductive Medicine (ASRM) taking place in October in Denver, USA.
The researchers led by Conrado Avendaño, a biochemist specializing in andrology, in collaboration with Ariela Mata, reproductive biology specialist and César Sánchez Sarmiento, director of the medical center, among others, demonstrated that the motility of spermatozoa is impaired when these cells are exposed to the radiation from laptops, according to a report published in the Córdoba newspaper “La Voz” (in Spanish).
For this study, the researchers evaluated semen samples from healthy donors with no history of recent illnesses. Each sample was divided into two equal fractions, which were placed in separate temperature-controlled rooms. One of the sub-samples was incubated under a laptop connected to the Internet, to replicate the conditions that occur when a man places the computer on his lap.
The findings are important because previous studies on reproductive medicine have shown that some of the problems in fertilization and embryonic development are caused by damage in the DNA molecules of the sperm.
While agreeing that further research on the matter is required, the researchers advise men to avoid holding laptop computers on the legs, “especially if they are connected to Internet through Wi-Fi.”
This research brings new knowledge on the effects of electromagnetic fields (EMF) on human health. EMF levels from Wi-Fi devices are much lower than those emitted by mobile phones, and there is less public concern on potential health issues for wireless LAN devices. The Health Protection Agency (HPA) claims that if a person spends one year in a Wi-Fi hot-spot, they will receive a dose of radio waves equivalent to a 20-minute call on a mobile phone.
Often wireless access points are in close proximity to humans, but the drop off in the already low power over distance is fast, following the inverse-square law (*). Nonetheless, the results of this study suggest that when a laptop is operated for long periods, the close proximity to the source of the EMF may affect a male user sensitive reproductive cells causing damage to DNA and reducing sperm cell motility.