Pithovirus: 30,000-year-old giant virus ‘comes back to life’


A new virus called Pithovirus sibericum has been isolated from 30,000 year old Siberian permafrost. It is the oldest DNA virus of eukaryotes ever isolated, showing that viruses can retain infectivity in nature for very long periods of time.

Pithovirus was isolated by inoculating cultures of the amoeba Acanthamoeba castellani with samples taken in the year 2000 from 30 meters below the surface of a late Pleistocene sediment in the Kolyma lowland region. This amoeba had been previously used to propagate other giant viruses, such as Mimivirus and Pandoravirus. Light microscopy of the cultures revealed the presence of ovoid particles which were subsequently shown by electron microscopy to resemble those of Pandoravirus. Pithovirus particles are flask-shaped and slightly larger than Pandoravirus – 1.5 microns long, 500 nm in diameter, encased by a 60 nm thick membrane. One end of the virus particle appears to be sealed with what the authors call a cork (photo). This feature, along with the shape of the virus particle,  inspired the authors to name the new isolate Pithovirus, from the Greek word pithos which refers to the amphora given to Pandora. The name therefore refers both to the morphology of the virus particle and its similarity to Pandoravirus.

Although the Pithovirus particle is larger than Pandoravirus, the viral genome – which is a double-stranded molecule of DNA – is smaller, a ‘mere 610,033 base pairs’, to use the authors’ words (the Pandoravirus genome is 2.8 million base pairs in length). There are other viruses with genomes of this size packed into much smaller particles – so why is the Pithovirus particle so large? Might it have recently lost a good deal of its genome and the particle size has not yet caught up? One theory of the origin of viruses is that they originated from cells and then lost genes on their way to becoming parasitic.

We now know of viruses from two different families that have similar morphology: an amphora-like shape, an apex, and a thick electron-dense tegument covered by a lipid membrane enclosing an internal compartment. This finding should not be surprising: similar viral architectures are known to span families. The icosahedral architecture for building a particle, for example, can be found in highly diverse viral families. The question is how many viruses are built with the pithovirus/pandoravirus structure. Prof. Racaniello’s guess would be many, and they could contain either DNA genomes. We just need to look for them, a process, as the authors say that ‘will remain a challenging and serendipitous process’.

Despite the physical similarity with Pandoravirus, the Pithovirus genome sequence reveals that it is barely related to that virus, but more closely resembles members of the Marseillviridae, Megaviridae, and Iridoviridae. These families all contain large icosahedral viruses with DNA genomes.  Only 32% of the 467 predicted Pithovirus proteins have homologs in protein databases (this number was 61% for Mimivirus and 16% for Pandoravirus). In contrast to other giant DNA viruses, the genome of Pithovirus does not encode any component of the protein synthesis machinery. However the viral genome does encode the complete machinery needed to produce mRNAs. These proteins are present in the purified Pithovirus particle. Pithovirus therefore undergoes its entire replication cycle in the cytoplasm, much like other large DNA viruses such as poxviruses.

Pithovirus is an amazing virus that hints about the yet undiscovered viral diversity that awaits discovery. Its preservation in a permafrost layer suggests that these regions might harbor a vast array of infectious organisms that could be released as these regions thaw or are subjected to exploration for mineral and oil recovery. A detailed analysis of the microbes present in these regions is clearly needed, both by the culture technique used in this paper and by metagenomic analysis, to assess whether any constitute a threat to animals.

The above story is reprinted from materials provided by Virology blog: About Viruses and Viral Disease.

Nanomotors Steered Inside Living Human Cells For the First Time


A group of researchers from Penn State have pushed the realm of possibilities for nanotechnology further as they have successfully steered a nanomotor inside of a human cell. This is the first time this feat has been accomplished. The team of chemists, biologist, and engineers was led by Tom Mallouk and has been published in Angewandte Chemie International Edition.

photo credit: Mallouk Lab/ Penn State

Nanomotors have been studied in vitro more more than a decade now. The hope is that eventually, they could be used inside of human cells for biomedical research. This nanotechnology could revolutionize drug delivery and even perform surgery in order to increase quality of life in the least invasive way possible. The earliest models were nonfunctional in biological fluid due to their fuel source. A huge breakthrough came later when the nanomotors were able to be powered externally via acoustic waves. The nanomotors used inside the human cells for the latest study were controlled by the ultrasonic waves as well as magnets.

The researchers used HeLa cells, derived from a long-lived line of cervical cancer cells, to study the nanomotors. Getting past the cell membrane was easy, as the cells ingested the nanomotors themselves. Once inside, the ultrasound was turned on and the nanomotors began to spin and move around the cell. If the signal was turned up even higher, the nanomotor can spin like a propeller, chopping up the organelles inside the cell. They were even able to puncture the cell membrane, finishing off the death sentence. Used at low powers, the nanomotor was able to move around the cell without causing any damage.

The addition of magnets gave an important advantage: steering. The motors are also able to be controlled individually, allowing the operator to take a much more targeted approach to killing diseased cells.

Ultimately, the researchers hope that one day the rocket-shaped gold nanorods will be able to move in an out of the cells without causing damage. The individual units could communicate with one another to target disease in the body, maximizing the efficacy of the treatment or even making the correct diagnosis. Working toward the goal of creating such advanced nanotechnology will not only push the boundaries of nanoengineering, but will increase our understanding of chemical and biological processes at the cellular level as well.

“The assembly of a rotating HeLa cell/gold rod aggregate at an acoustic nodal line in the xy plane. The video was taken under 500X overall magnification except for 00:23 – 00:32 and 01:16 – 01:42, where a 200X overall magnification was used.” Credit: Mallouk Lab, Penn State

“Very active gold nanorods internalized inside HeLa cells in an acoustic field. A demonstration of very active gold nanorods internalized inside HeLa cells in an acoustic field. This video was taken under 1000X magnification in the bright field, with most of the incoming light blocked at the aperture.” Credit: Mallouk Lab, Penn State

 

The above story is reprinted from materials provided by I F* Love Science.

Can ‘Robotic’ Pills Replace Injections?


The adage “Take two aspirin and call me in the morning” is destined for a futuristic makeover. Doctors may just as easily recommend swallowing sophisticated gadgets instead.

That is the hope of prolific inventor Mir Imran, who has created a robotic pill to replace injectable drugs for chronic conditions such as diabetes. The gadget, in preclinical studies and backed by Google Inc.’s venture-capital unit, consists of an ingestible polymer and tiny hollow needles made of sugar that are designed to safely deliver drugs to the small intestine.

Such a pill would have seemed unthinkable years ago. But advancements in technology and scientific research have recently led to two federally approved robotic pills.

The Food and Drug Administration earlier this month cleared the PillCam, a pill-sized camera from Given Imaging Ltd. that photographs human insides in a hunt for colon polyps. Another company, Proteus Digital Health Inc., received clearance a year and a half ago to put ingestible sensors inside pills to help patients and doctors determine how many they have taken.

Mr. Imran’s pill hasn’t yet been tested in humans, so it is probably still at least a year away from even seeking federal approval. It also would require substantial financing to manufacture millions of pills. But if it is successful, the gadget has the potential to disrupt a multibillion-dollar market for injectable drugs and make life easier for millions of sufferers of conditions such as diabetes and rheumatoid arthritis.

Mr. Imran is a safer bet than most entrepreneurs. The Indian-born founder of the research lab and business incubator InCube Labs in Silicon Valley has founded more than 20 medical-device startups, a dozen of which have been acquired by companies such as Medtronic Inc. He owns over 300 patents and helped develop the first implantable cardioverter defibrillator to correct irregular heartbeats.

Rani Therapeutics, the startup formed at InCube Labs to commercialize the robot pill, last year raised funds from Google Ventures and angel-investment fund VentureHealth.

Blake Byers, the Google Ventures general partner who spearheaded the investment, says Mr. Imran may be achieving one of the “holy grails” for biotechnology by figuring out how to deliver protein-based drugs such as basal insulin to the body without the use of a syringe.

“This investment is not exactly in our wheelhouse, but we’re open to people who can change our minds,” Mr. Byers said. “This one really stood out as a huge clinical need; $110 billion is spent in the U.S. every year on biologics, all of them injectable.”

Drugs used to treat a variety of chronic conditions, including diabetes, rheumatoid arthritis, osteoporosis and multiple sclerosis, can’t be delivered in pill form because stomach acids break down the proteins.

Mr. Imran’s idea is an “autonomic robotic delivery system” that can stay intact in the stomach and small intestine long enough to deliver enough of the drug. The body’s natural digestive processes activate the pill to perform a series of functions even without any electronics.

As the pH level, or acidity, builds up in the intestine, the outer layer of the polymer pill casing dissolves, exposing a tiny valve inside the device that separates two chemicals, citric acid and sodium bicarbonate.

When the valve becomes exposed, the chemicals mix together to create carbon dioxide. This acts as an energy source, gently inflating a balloon-like structure that is outfitted with needles made of sugar and preloaded with drugs.

The needles push into the intestinal wall, which has no pain receptors. Once lodged there, they detach from the gadget and slowly dissolve, while the balloon and polymer casing pass from the body.

In numerous attempts over the past 40 years to make insulin and other drugs available in pill form, pharmaceutical companies have been able to create coatings so tough that pills can reach the small intestine. But once there, they are attacked by enzymes, which has compromised the pills and prevented significant amounts of the drug from reaching the patient.

In preclinical studies, Rani Therapeutics has shown that its robotic pill can boost drug absorption at least as high as syringes can, Mr. Imran said.

“I am guardedly optimistic, and I say guardedly because there is still a lot of work left to do,” said Elliott Sigal, who several months ago retired from drug maker Bristol-Myers Squibb Co. His 16-year run at the drug maker included top posts in drug discovery and development and a nearly 10-year tenure as the head of research and development.

“Rani’s engineering-based approach to this is very innovative,” said Mr. Sigal, who doesn’t have a financial stake in the business. “He is getting results that I have not seen before. It hasn’t been tried in human patients yet, and things do sometimes fail at that level. But if the [trials] data continues, there will be a great deal of pharma interest.”

Mr. Imran said pharmaceutical companies, which would license the technology for use with their own drugs, have already expressed interest. He declined to give further details.

Rani Therapeutics will spend another year testing the robot pill, he said, in the hope that it will have definitive clinical data in 2015.

If the data back up his claim about the pill, it could not only help millions of patients ditch their syringes and stick-pens, but it could remove another barrier for a range of early-stage treatments that currently have no safe avenue into the body, said Google Ventures’ Mr. Byers.

Here is also a short video: Can ‘Robotic’ Pills Replace Injections?

The above story is reprinted from materials provided by The Wall Street Journal.

3D Model of Child’s Heart Helps Surgeons Save Life


A 14-month-old boy in need of life-saving heart surgery is the beneficiary of a collaboration among University of Louisville engineers, physicians and Kosair Children’s Hospital.

Roland Lian Cung Bawi of Owensboro was born with four congenital heart defects and his doctors were looking for greater insights into his condition prior to a Feb. 10 operation.

Philip Dydynski, chief of radiology at Kosair Children’s Hospital, recently had toured the Rapid Prototyping Center at the University of Louisville’s J.B. Speed School of Engineering and became impressed with the 3D printing capabilities available there.

He asked the center’s operations manager, Tim Gornet, if a 3D model of the child’s heart could be constructed using a template created by images from a CT scan to allow doctors to better plan and prepare for his surgery. No problem, Gornet said.

The result of the Rapid Prototyping Center’s work was a model heart 1.5 times the size of the child’s. It was built in three pieces using a flexible filament and required about 20 machine hours – and only about $600 — to make, Gornet said.

Once the model was built, Erle Austin III, cardiothoracic surgeon with University of Louisville Physicians, was able to develop a surgical plan and complete the heart repair with only one operation.

“I found the model to be a game changer in planning to do surgery on a complex congenital heart defect,” he said.

Roland was released from Kosair Children’s Hospital Feb. 14 and returned Feb. 21 for checkups with his doctors. His prognosis is good.

That’s good news for Gornet, whose work at the Rapid Prototyping Center routinely benefits manufacturers and heavy industry. Helping surgeons save a life was new territory for him.

“Knowing we can make somebody’s life better is exciting,” he said.

Here is also a short video:  UofL Engineers Construct 3D Heart Model

The above story is reprinted from materials provided by University of Louisville Today.

Increasing Brain Acidity May Reduce Anxiety


Animal study highlights potential new target for treating anxiety disorders

Increasing acidity in the brain’s emotional control center reduces anxiety, according to an animal study published February 26 in The Journal of Neuroscience. The findings suggest a new mechanism for the body’s control of fear and anxiety, and point to a new target for the treatment of anxiety disorders.

Anxiety disorders, which are characterized by an inability to control feelings of fear and uncertainty, are the most prevalent group of psychiatric diseases. At the cellular level, these disorders are associated with heightened activity in the basolateral amygdala (BLA), which is known to play a central role in emotional behavior.

Many cells in the BLA possess acid-sensing ion channels called ASIC1a, which respond to pH changes in the environment outside of the cell. Maria Braga, DDS, PhD, and colleagues at the Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, found that activating ASIC1a decreased the activity of nearby cells and reduced anxiety-like behavior in animals. These findings add to previous evidence implicating the role of ASIC1a in anxiety.

“These findings suggest that activating these channels, specifically in fear-related areas such as the amygdala, may be a key to regulating anxiety,” explained Anantha Shekhar, MD, PhD, who studies panic disorders at Indiana University and was not involved in this study. “Developing specific drugs that can stimulate these channels could provide a new way to treat anxiety and fear disorders such a post-traumatic stress and panic disorders.”

To determine the effect ASIC1a activation has on neighboring cells, Braga’s group bathed BLA cells in an acidic solution in the laboratory and measured the signals sent to nearby cells. Lowering the pH of the solution decreased the activity of cells in the BLA.

Activating ASIC1a also affected animal behavior. When the researchers administered a drug that blocks ASIC1a directly into the BLA of rats, the rats displayed more anxiety-like behavior than animals that did not receive the drug. In contrast, when rats received a drug designed to increase the activity of ASIC1a channels in the BLA, the animals displayed less anxiety-like behavior.

“Our study emphasizes the importance of identifying and elucidating mechanisms involved in the regulation of brain function for the development of more efficacious therapies for treating psychiatric and neurological illnesses,” Braga said. While the findings suggest that drugs targeting ASICs may one day lead to novel therapies for anxiety disorders, Braga noted that “more research is needed to understand the roles that ASIC1a channels play in the brain.”

Link to the article:

The Journal of Neuroscience

2013 in Review


The WordPress.com stats helper monkeys prepared a 2013 annual report for my blog.

Here’s an excerpt:

A New York City subway train holds 1,200 people. This blog was viewed about 7,600 times in 2013. If it were a NYC subway train, it would take about 6 trips to carry that many people.

Click here to see the complete report.

Bell’s Palsy

September 11, 2013 2 comments

I figured it is about time to write something about the blog’s title, bell’s palsy, since I’ve seen there are a lot of people searching for this topic about facial paralysis.

Bell’s palsy is a common condition that presents with an acute onset of lower motor neuron (LMN – could say like  peripheral nerves) facial weakness affecting the muscles on one side of the face.

People of all ages may be affected, including children, although it is most common in patients aged 30-50 years. The exact cause in not known, but there are certain conditions known to be responsible.

If we take a look in pathogenesis, how the condition evolves, we see that there is segmental demyelination in a local conduction block proximally. And what this actually means? Every nerve has its sheath around that is made of substance called myelin. This myelin sheath does not cover the whole nerve, but in segments, leaving tiny gaps, called Nodes of Ranvier (take a look at the picture below). And these gaps are like capacitors that stores electrical charge and allows bursts of electric impulses (know as action potentials) to move along the neuron in a saltatory fashion. Think of it as the action potential would jump from one of these gaps to the next one. This actually prevents loosing the charge. Now imagine that you widen this gap. This slows the nerve conduction, spread it even more and you get a block, conduction block. Now you cannot get the full use of that nerve leaving you weakness.

Since this conduction block happens proximally (closer to its origin), it allows a relatively rapid and complete recovery in about 85% of cases. This is because myelin rapidly regenerates. In others, axonal degeneration occurs, which will produce a severe paralysis. Again, think of it as the whole neuron is cut, and that is why it is so severe. Often this is then followed by incomplete recovery associated with aberrant re-innervation, that is, fibers from the periocular muscles my regenerate and supply the mouth, and vice versa. Such faulty re-innervation may lead to “jaw-winking”, and even hemifacial spasm. Where axonal degeneration has occurred, electromyography of the facial muscles will show fibrillation and features of denervation, although these changes may not appear until some 10 days after the onset. In some instances the pathogenesis is a mixture of axonal degeneration and demyelination.

Ok, let’s leave this aside and let’s carry on and look how this condition actually presents clinically. Normally patients may present with pain in or behind the ear preceding or appearing with the development of facial weakness. There is inability to close the eye or move the lower face and mouth on one side of the face.

The lack of blinking leads to tears spilling out of the eye, which waters to cause complaints of blurred vision. The cheek is flaccid and saliva and fluids may escape from the corner of the mouth. The weakness commonly progresses over 24-72 hours to reach a maximum. In many patients there are complaints of numbness in the affected side of the face, although trigeminal sensation is spared and there should be no weakness of jaw movement, since it is supplied by the motor root of the trigeminal nerve. Trigeminal sensation is sensation on the skin of the face, because sensory innervation of it comes from fifth cranial nerve – trigeminal nerve. Hence the name.

About 40-50% of patients are aware of disturbed taste on the ipsilateral anterior part of the tongue (ipsilateral means it is on the same side as the lesion). This points to a lesion in the distal part of the facial nerve below the geniculate ganglion, but above the origin of the chorda tympani (branch of facial nerve that is responsible for taste). Many patients also notice hyperacusis (over-sensitivity to certain frequency ranges of sound and difficulty tolerating everyday sounds, some of which may seem unpleasantly loud) because the stapedius muscle (very small muscle that moves the smallest bone in the human body and makes us hear) is supplied by a branch of the facial nerve, which leaves the nerve in the facial canal proximal to the chorda tympani.

If a zoster infection is responsible, there will be herpetic vesicles on the pinna (the visible part of the ear that resides outside of the head, also called auricle or auricula) or in the external auditory canal on the affected side. Ramsay Hunt described a herpetic infection of the geniculate ganglion with the development of an acute facial palsy – Hunt’s syndrome. In some of these patients the 8th cranial nerve (auditory nerve, responsible for hearing) may also be infected, producing acute vertigo, deafness and tinnitus (ringing of the ears). A few patients may show a bilateral (on both sides) facial palsy of lower motor neuron (LMN) pattern; this may appear as part of a Guillain-Barre syndrome, from Lyme disease, from sarcoidosis or even carcinomatous meningitis.

About 85% of patients show signs of improvement within some 3 weeks of the onset. About 70% of patients recover normal function in the face but some 16% are left with asymmetry, signs of aberrant re-innervation and some weakness. An incomplete palsy at the onset or signs of recovery starting within 3-4 weeks usually are good prognostic features for recovery. This is mirrored in the electrophysiological findings. In the more severely affected, where axonal degeneration has taken place, recovery is slower and often incomplete. Recurrent facial palsies require more intensive investigation to exclude any compressive lesion on the middle ear or skull base, and to look for any systemic upset such as sarcoidosis, hypertension, diabetes.

Normally when there is suspicion of Bell’s palsy several investigations are made. Such as blood tests. Full blood count, erythrocyte sedimentation rate (ESR), fasting glucose levels, tests for Borrelia. Of course there is imaging; in selected patients MRI and/or CT scanning, chest X-ray. Electromyography (EMG) studies as these may assess the severity of damage and help in prognosis; they may also indicate a more widespread neuropathy. ENT examination…

Once all the tests are conclusive and the Bell’s palsy diagnosis is made, patients can undergo treatment. There appears to be little difference in outcome between patients treated with steroids and those who are not. Many doctors believe that a short intensive course of steroids given within 5-7 days of the onset of palsy may reduce the swelling of the facial nerve and so prevent axonal degeneration. Prednisolon 40 mg daily for 5 days and then tapered off over the next week is a typical regimen. It has been suggested that such a course should be given to all patients seen acutely with a complete palsy at the time of consultation or with impaired taste.

Because of the possible infective causation by herpes virus, acyclovir has also been used in treatment of an cute facial palsy. This certainly should be given if a zoster infection (Hunt’s syndrome) is suspected. The combination of acyclovir with steroids in those patients with complete facial palsies has also been used. Surgical decompression of the facial nerve has had its supporters over the years, although there has been no rigorous controlled trial to indicate benefit and as over 70% of patients will make a full recovery with no treatment it is hard to justify the surgical risks.

Care of the eye is always important if there is incomplete lid closure but as the cornea is not anesthetic, the patient will be aware of any intruding foreign body. Occasionally it may be necessary to suture the lids partially together, a tarsorrhaphy, to protect the eye.

In those patients left with marked residual weakness or asymmetry, a number of surgical measures may be used to try to improve their appearance. These include plastic surgery with implants of soft tissues to restore the contours. Such measures will improve the symmetry of the face at rest but are by no means a ‘cure’.