Monthly Archives: April 2012

Flag flown over Afghanistan in honor of Animal Hospital goes on display

 flagA new display featuring a special American flag now adorns Cornell University Hospital for Animals’ waiting room. To express thanks for CUHA’s life-saving services, Jessica and Mark Chamberlin gifted the folded flag to CUHA after Mark returned from military duty in Afghanistan, where he had flown it from a Chinook helicopter in honor of CUHA’s doctors, students, and staff.

While serving as a pilot in Afghanistan from October 2010 to October 2011, U.S. Army Chief Warrant Officer 3 Mark Chamberlin received bad news from his wife back home. Lucy, their husky, had been diagnosed with both acute and chronic liver failure. The prognosis looked bleak but Jessica took Lucy to Cornell to see what could be done.

“A biopsy revealed Lucy had hepatitis, extreme liver inflammation,” said Dr. Andrea Johnston, a third-year resident in Hepatology who led the case. “Much of the damage is irreversible and her liver will never function normally, but we were able to get the inflammation under control and develop a nutritional regime specially adapted to her condition. Jessica and Mark worked diligently with the new diet, home-cooking all the food—it’s clear how committed they are to helping Lucy.”

Lucy’s history of hardship began in an abusive dog yard in Alaska. When she got her foot caught in a chain, her former owners cut it off with a chainsaw and left her without medical care. Animal control officers investigating the dog yard found the injured husky and brought her to the animal hospital where Jessica worked as a licensed veterinary technician.

“It took a week to get the infection under control and we had to amputate her leg,” said Jessica. “I spent so much time with her that I got attached and brought her home. She’s been like a child to us ever since.”

The Chamberlin’s parent-like dedication continued through Lucy’s latest ordeal. On the couple’s 10th anniversary, instead of going on the vacation they had originally planned, Jessica and Mark spent their time in Ithaca supporting Lucy during her biopsy and liver care. After Lucy’s initial recovery, they spent time cooking Lucy’s special diet and nursing her back to health.

Their work paid off, and when Mark returned to Afghanistan to lead the flight mission “Operation Enduring Freedom XI,” he flew a flag from the CH-47F “Chinook” helicopter in CUHA’s honor.

“When we first brought Lucy to Cornell we thought she only had a couple weeks,” said Jessica. “Cornell was able to save our girl, and we wanted to do something special to honor the people at the hospital. We are so grateful that Cornell was an option and that all of the doctors and staff were so kind and helpful in getting Lucy back on her feet. We are honored that Cornell has chosen to display the flag in the lobby.”

The flag is proudly displayed in a wooden plaque along with a certificate signed by Mark Chamberlin and the four other officers who flew during the mission under his command. It can be viewed in CUHA’s waiting room to the right of the reception desk window.

flag

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http://www.vet.cornell.edu/news/Flag.cfm

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First discovery of cells expelling mitochondria uncovers newfound survival tactic

An ancient union between cell and organelle has shown the first sign of fracture, challenging common conceptions of a primordial partnership all multicellular organisms rely on to live. Cornell researchers have recorded the first direct evidence of cells expelling intact mitochondria, the cellular machinery responsible for energy production.

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An illustrated mitochondrion

Malfunctioning mitochondria produce free-radicals that damage cells, contributing to aging, mitochondrial myopathies, and disorders ranging from schizophrenia, bipolar disorder, and dementia to Parkinson’s disease and multiple sclerosis. The newfound breakup behaviour, described in Mitochondrion 2011 Nov.11(6), may be an early cell-survival strategy to escape the toxic effects of damaged mitochondria.

“It is very surprising to see living cells actively jettisoning vital parts of themselves,” said Dr. Theodore Clark, immunologist at the College of Veterinary Medicine. “This is the first time full mitochondria have been found outside cells and it may account for 15 years’ worth of unexplained data showing mitochondrial DNA and protein in extracellular spaces. We think these cells’ behaviour reveals a newfound survival tactic deeply rooted in evolution.”

Today’s mitochondria evolved from freewheeling bacteria that settled down in other cells two billion years ago. In exchange for food and shelter, the bacteria helped cells break nutrients into energy. These helpful tenants became modern mitochondria: the power-plants inside all cells of nearly every animal, plant, fungus, and protozoan.

Yet domestic disputes over cellular housekeeping may spur divorce, according to findings from Clark’s lab showing mitochondria moving out.

Graduate student Yelena Bisharyan discovered this while studying an unrelated phenomenon: escape stunts of the fish parasite Ichthyophthirius multifiliis. Clark’s lab had observed these parasitic protozoa avoiding destruction by shaking off attacking antibodies and exiting their hosts and wanted to see how they escaped.

“Attacking antibodies bind to the parasite’s cell surface,” said Clark. “We suspected that when antibodies attach, the parasite can shed them by breaking off its surface proteins – sort of like a lizard shedding its tail.”

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Tetrahymena, a protozoan, sheds proteins and mitochondria in response to attacking antibodies

Applying antibodies to parasites in culture, Bisharyan observed the reactions of Ichtyophthirius and Tetrahymena, another ciliated protozoan used as a model system to study fundamental biological principles across species.

Using negative staining and electron microscopy techniques, Bisharyan recorded parasites sacrificing their surface proteins to rid themselves of attached antibodies. Yet her images also captured something completely unexpected: intact and fragmented mitochondria coming out of the parasite’s cells.

This surprising finding won Bisharyan an invitation to present at one of the 2011 Gordon Research Conferences, a prestigious international forum showcasing major discoveries across scientific fields.

“Mitochondria experts were very excited to see this,” said Clark. “Over the past 15 years several papers have reported mitochondrial DNA and proteins floating outside mammalian cells. No one knew how or why they got there. What we’ve found in protozoa may help explain similar processes in mammals.”

Mitochondria (m) are pushed to the surface and jettisoned from the cell

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Mitochondria (red) discovered outside cells

Certain cellular stressors can trigger mitochondrial expulsion, according to Bisharyan’s study. In protozoa, for example, not only antibodies but also heat shock can induce this effect. These stressors elevate calcium levels within the cell, possibly damaging mitochondria and causing them to produce toxic free-radicals.

“Our hypothesis is that mitochondria become poisoned and these protozoa have found a way to rid themselves of the damaged powerplants before they can cause further harm,” said Clark. “We think their behaviour reveals an early adaption to cellular stress that other species may share.”

Mammals and fish parasites may bear little family resemblance these days, but a common ancestor may have equipped both with emergency mitochondria-removal systems. Understanding this process could illuminate new approaches to reducing mitochondria-induced damage in humans and other animals.

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Cornell University College of Veterinary Medicine news

http://vet.cornell.edu/news/Mitochondria.cfm