Posts Tagged ‘viruses’

Some COVID-19 Pneumonia Cases Are Like Acute Respiratory Distress Syndrome

Reporter: Irina Robu, PhD

Doctors around the world are still learning about the novel coronavirus (COVID-19), but it’s obvious that the most serious cases include severe respiratory symptoms that can damage a person’s lungs. The COVID-19 can cause pneumonia which can lead to a more severe condition called acute respiratory distress syndrome (ARDS). Fluid buildup in the lungs prevents them from filling with air, decreasing the amount of oxygen that reaches the bloodstream.

At the start, COVID-19 pneumonia presents with the resulting characteristics such as low elastance (the amount of gas in the lung), low ventilation-to-perfusion, low lung weight and low lung recruit ability (amount of non-aerated tissue). When the coronavirus reaches the lungs, it causes viral pneumonia. The lungs can then become filled with fluid. The COVID-19 disease can be mild, but more severe cases may require hospitalization. The infections associated with the disease can  escalate to the point a patient develops ARDS. The higher mortality rate for COVID-19 patients who develop ARDS may be attributable to other symptoms of the coronavirus.

Like many viruses, the respiratory droplets related with COVID-19 attach to the back of a person’s throat or nose, then move through the respiratory tract. The human body replies to viruses by trying to fight them off, which causes inflammation. Some scientists also suggested that pneumonia that presents in COVID-19 tends to be bilateral, meaning it affects both lungs. Fluid buildup in the lungs prevents them from filling with air, decreasing the amount of oxygen that reaches the bloodstream.

Medical experts are correspondingly trying to determine if pneumonia caused by the coronavirus is more likely to become severe and cause ARDS. The limited number of tests performed on COVID-19 patients makes it impossible to say at this time. Doctors may prescribe antiviral medication to treat pneumonia caused by the flu. It’s unclear if any medicines are reliable for patients diagnosed with the coronavirus.

Pneumonia caused by a virus tends to show up on CT scans as hazy white patches known as ground-glass opacities. The doctors at Mount Sinai Health System in New York City who studied CT scans from COVID-19 patients noticed those hazy patches tended to cluster around the edge of both lungs.

Imaging the lungs in a patient who may have COVID-19 can be problematic, since imaging machines necessitate thorough disinfecting after they’re used to take an X-ray or CT scan of a patient suspected of having the coronavirus.



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Memory Gene Goes Viral

Reporter: Irina Robu, PhD

A gene crucial for learning, called Arc can send genetic material from one neuron to another by using viruses was discovered by two independent team of scientist from University of Massachusetts Medical School and University of Utah which was published in Cell.  According to Dr. Edmund Talley, a program director at National Institute of Neurological Disorders and Stroke “this work is a great example of the importance of basic neuroscience research”.

Arc plays an important role in the brain’s ability to store new information, however little is known of how it works. According to the University of Utah scientists, research into the examination of the Arc gene began by introducing it into bacterial cells. When the cells made the Arc protein, it clumped together into a form that resembled a viral capsid, the shell that contains a virus’ genetic information. The Arc “capsids” appeared to mirror viral capsids in their physical structure in addition as their behavior and other properties.

At the same time, University of Massachusetts scientist led by Vivian Budnik, Ph. D and Travis Thomson, Ph.D. set out to scrutinize the contents of tiny sacks released by cells called extracellular vesicles. Their experiments in fruit flies revealed that motor neurons that control the flies’ muscles release vesicles containing a high concentration of the Arcgene’s messenger RNA (mRNA), the DNA-like intermediary molecule cells use to create the protein encoded by a DNA sequence.

Both groups similarly found evidence that Arc capsids contain Arc mRNA and that the capsids are released from neurons inside those vesicles. Also, both groups suggest that Arc capsids act like viruses by delivering mRNA to nearby cells. Furthermore, Dr. Shepherd’s team presented that the more active neurons are, the more of those vesicles they release. Dr. Shepherd’s group grew mouse neurons lacking the Arc gene in petri dishes filled with Arc-containing vesicles or Arc capsids alone. They revealed that the formerly Arc-less neurons took in the vesicles and capsids and used the Arc mRNA contained within to produce the Arc protein themselves. Finally, just like neurons that naturally manufacture the Arc protein, those cells made more of it when their electrical activity increased.

Both groups of scientists plan to examine why cells use this virus-like strategy to shuttle Arc mRNA between cells and which might allow the toxic proteins responsible for Alzheimer’s disease to spread through the brain.



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