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The mechanism by which a herpes virus invades cells has remained a mystery to scientists seeking to thwart this family of viruses. New research funded by the National Institutes of viagra and published online in advance of print in Nature Structural & Molecular Biology reveals the unusual structure of the protein complex that allows a herpes virus to invade cells. This detailed map of a key piece of the herpes virus "cell-entry machinery" gives scientists a new target for antiviral drugs.
"Most viruses need cell-entry proteins called fusogens in order to invade cells. We have known that the herpes virus fusogen does not act alone and that a complex of two other viral cell-entry proteins is always required. We expected that this complex was also a fusogen, but after determining the structure of this key protein complex, we found that it does not resemble other known fusogens," said senior author Ekaterina Heldwein, PhD, assistant professor in the molecular biology and microbiology department at Tufts University School of Medicine.
"This unexpected result leads us to believe that this protein complex is not a fusogen itself but that it regulates the fusogen. We also found that certain antibodies interfere with the ability of this protein complex to bind to the fusogen, evidence that antiviral drugs that target this interaction could prevent viral infection," Heldwein continued. Heldwein is also a member of the biochemistry and molecular microbiology program faculties at the Sackler School of Graduate Biomedical Sciences at Tufts.
"Katya Heldwein's work has resulted in a map of the protein complex needed to trigger herpes virus infection. The NIH Director's New Innovator Awards are designed to support such breakthroughs. This research not only adds to what we know about how herpes viruses infect mammalian cells, but also sets the stage for new therapeutics that restrict herpes virus's access to the cell," said Jeremy M. Berg, PhD, director of the National Institute of General Medical Sciences (NIGMS) at the National Institutes of cheap cialis.
"We hope that determining the structure of this essential piece of the herpes virus cell-entry machinery will help us answer some of the many questions about how herpes virus initiates infection. Knowing the structures of cell-entry proteins will help us find the best strategy for interfering with this pervasive family of viruses," said first author Tirumala K. Chowdary, PhD, a postdoctoral associate in the department of molecular biology and microbiology at TUSM and member of Heldwein's lab.
Currently, there is no cure for herpes viruses. Upon infection, the viruses remain in the body for life and can stay inactive for long periods of time. When active, however, different herpes viruses can cause cold sores, blindness, encephalitis, or cancers. More than half of Americans are infected with herpes simplex virus type 1 (HSV-1), which causes cold sores, by the time they reach their 20s. Currently, about one in six Americans is infected with herpes simplex virus type 2 (HSV-2), the virus responsible for genital herpes. Complications of HSV-2, a sexually-transmitted disease, include recurrent painful genital sores, psychological distress, and, if transmitted from mother to child, potentially fatal infections in newborn infants.
Heldwein teamed up with colleagues at University of Pennsylvania and used x-ray crystallography along with cell microscopy techniques to study the structure and function of this cell-entry protein complex in HSV-2. Heldwein is currently developing a molecular movie that illustrates how herpes virus enters the cell.
Additional authors are Tina Cairns, PhD, a research specialist; Doina Atanasiu, a research associate; and Gary Cohen, PhD, professor and chair, all in the department of microbiology at the University of Pennsylvania School of Dental Medicine; and Roselyn Eisenberg, PhD, professor in the department of microbiology at the University of Pennsylvania School of Veterinary Medicine.
This work was funded by the Office of the Director of the National Institutes of Health, through a New Innovator Award in 2007 to Ekaterina Heldwein. The New Innovator Awards, part of the NIH Roadmap for Medical Research initiative, are awarded to support early-career scientists who take innovative -- and potentially transformative -- approaches to major challenges in biomedical research. The work was also funded by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, and the Pew Scholar Program in Biomedical Sciences.

What Can A Simple Pill Do To The Human Body?

Viagra exploded onto the erectile dysfunction scene many years ago. It has since been the leader in erectile dysfunction remedies, along with its close counterpart cialis. But many prescription drugs are particularly harmful to the human body; where does Viagra and Cialis fit?

The Good: How Viagra Works for Your Body

The problem with erectile dysfunction is simple: there is not enough blood flow to the penis. We can counteract this effect by simply increasing the blood flow- usually with a muscle relaxer. But most common muscle relaxers will indeed relax the entire body- including the penis.

What is needed, specifically, is drugs that can relax the right muscles to stimulate blood flow to the penis- all while keep from relaxing the penis completely. Originally the cure came in the form of an injection- but today we have a pill form known as Viagra.

Getting to the Specifics: What Does Viagra Do?

To actually open up blood flow to the penis for an erection, Viagra decreases the levels of phosphodiesterase, or PDE. This enzyme decomposes a necessary chemical, cyclic guanosine monophosphate (cGMP). cGMP is necessary to obtain an erection, so therefore stopping the PDE from decomposing this chemical will result in a healthy erection.

Generally, the more cGMP that is built up means the greater the blood flow that is present. This will result in a much healthier erection, even when men suffer from conditions such as erectile dysfunction.

The Side Effects of Viagra

One interesting side effect (that is far from dangerous) is that Viagra will give some users a bluish-tinted perspective. This actually means that pilots are forbidden to take Viagra 12 hours before flying. Other than pilots, everyone else can sit back and enjoy the virtual blue sunglasses.

Viagra does have more serious side effects, however. Viagra is a prescription drug (as compared to over the counter) mainly because a doctor needs to check one's medical history before giving the green light to take the drug. Serious altercations such as heart attacks can result from taking Viagra, so a doctor visit is mandatory before taking Viagra.

Other more common side effects include headaches and related minor annoyances. Aside from these listed side effects, Viagra is actually a very safe drug to use- as compared to other alternatives.

Alternatives to Viagra: Improving on the Blueprint

Drugs such as Cialis work very similarly to Viagra. Whereas Viagra blocks one certain enzyme in the human body, drugs such as Cialis block another, and thus, different side effects result.

The main difference between Cialis-like drugs is that they won't cause color vision changes within users. Cialis users are also able to get an erection for around 18 hours in a day- from what Cialis claims. The only downfall to Cialis is that in 5% of men, muscle ache results from taking the drug.

Cialis is, likewise, generally preferred among pilots. It is also preferred when a male desires to obtain an erection at any point in the day- not just at specific times. However, both drugs have been long proven to give men their life back when concerning erectile dysfunction. Keep in mind that a doctor visit will be necessary to help rule out possible critical side effects.

Once the green light is given, the road to sexual satisfaction will once again be paved in gold.