Duke Research Blog

Following the people and events that make up the research community at Duke.

Author: Sarah Haurin (Page 1 of 2)

How A Bat’s Brain Navigates

Most of what we know about how the hippocampus, a region of the brain associated with memory formation and spatial representations, comes from research done on rodents. Rat brains have taught us a lot, but researchers in Israel have found an interesting alternative model to understanding how the hippocampus helps mammals navigate: Bats.

The Egyptian fruit bat proved the perfect subject for studies of mammalian navigation.

Weizmann Institute neurophysiologist Nachum Ulanovsky, PhD, and his team have looked to bats to understand the nuances of navigation through space. While previous research has identified specific cells in the hippocampus, called place cells, that are active when an animal is located in a specific place, there is not much literature describing how animals actually navigate from point A to point B.

Nachum Ulanovsky

Ulanovsky believes that bats are an ingenious model to study mammalian navigation. While bats have the same types of hippocampal neurons found in rats, the patterns of bats’ neurons’ firings more closely match that of humans than rats do.

Ulanovsky sought to test how bats know where they are going. Using GPS tracking equipment, his team found that wild bats that lived in a cave would travel up to 20 kilometers to forage fruit from specific trees. Night after night, these bats followed similar routes past perfectly viable food sources to the same tree over and over again.

The understanding of hippocampal place cells firing at specific locations doesn’t explain the apparent guided travel of the bat night after night, and other explanations like olfactory input do not explain why the bats fly over good food sources to their preferred tree.

The researchers designed an experiment to test how bats encode the 3D information necessary for this navigation. By letting the bats fly around and recording brain activity, Ulanovsky and team found that their 3D models are actually spherical in shape. They also found another type of hippocampal cells that encode the orientation the bat is facing. These head direction cells operate in a coordinate system that allows for a continuity of awareness of its orientation as the animal moves through space.

http://www.cell.com/cms/attachment/2091916945/2076305003/gr1_lrg.jpg

Ulanovsky found bats relied on memory to navigate toward the goal.

To understand how the bats navigate toward a specific goal, the researchers devised another experiment. They constructed a goal with a landing place and a food incentive. The bat would learn where the goal was and find it. In order to test whether the bats’ ability to find the goal was memory-based, or utilized the hippocampus, the researchers then conducted trials where the goal was hidden from the bats’ view.

To test whether the bats’ relied on memory, the Ulvanosky team measured the goal direction angle, or the angle between the bat’s head orientation and the goal. After being familiarized with the location of the goal, the bats tended toward a goal-direction angle of zero, meaning they oriented themselves toward the goal even when the goal was out of sight.

Continued research identified cells that encode information about the distance the bat is from the goal, the final piece allowing bats to navigate to a goal successfully. These hippocampal cells selectively fire when the bat is within specific distances of the goal, allowing for an awareness of location over distance.

While Ulanovsky and his team have met incredible success in identifying new types of cells as well as new functions of known cells in the hippocampus, further research in a more natural setting is required.

“If we study only under these very controlled and sterile environments, we may miss the very thing we are trying to understand, which is behavior,” Ulanovsky concluded.

By Sarah Haurin

Dopamine, Drugs, and Depression

The neurotransmitter dopamine plays a major role in mental illnesses like substance abuse disorders and depressive disorders, as well as a more general role in reward and motivational systems of the brain. But there are still certain aspects of dopamine activity in the brain that we don’t know much about.

Nii Antie Addy and his lab are interested in the role of dopamine in substance abuse and mood disorders.

Duke graduate Nii Antie Addy, PhD, and his lab at Yale School of Medicine have been focusing on dopamine activity in a specific part of the brain that has not been studied: the ventral tegmental area (VTA).

To understand the mechanisms underlying this association, Addy and his team looked at cue-induced drug-seeking behavior. Using classical conditioning, rats can be trained to pair certain cues with the reward of drug administration. When a rat receives an unexpected award, dopamine activity increases. After conditioning, dopamine is released in response to the cue more  than to the drug itself. Looking at the patterns of dopamine release in rats who are forced to undergo detoxification can thus provide insight into how these cues and neurotransmitter activity relate to relapse of substance abuse.

When rats are taught to self-administer cocaine, and each administration of the drug is paired with the cue, after a period of forced detoxification, the rodents continue to try to self-administer the drug, even when the drug is withheld and only the cue is presented. This finding again demonstrates the connection between the cue and drug-seeking behavior.

Studying the activity in the VTA gave additional insights into the regulation of this system. During the period of abstinence, when the rodents are forced to detox, researchers observed an increase in the activity of cholingergic neurons, or neurons in the brain system that respond to the neurotransmitter acetylcholine.

Using these observations, Addy and his team sought to identify which of the various receptors that respond to acetylcholine can be used to regulate the dopamine system behind drug-seeking behaviors. They discovered that a specific type of acetylcholine receptor, the muscarinic receptor, is involved in more general reward-seeking behaviors and thus may be a target for therapies.

Using Isradipine, a drug already approved by the FDA for treatment of high blood pressure, Addy designed an experiment to test the role of these muscarinic receptors. He co-opted the drug to act as a calcium antagonist in the VTA and thus increase dopamine activity in rodents during their forced detox and before returning them to access to cocaine. The outcome was promising: administration of Isradipine was associated with a decrease in the coke-seeking behavior of rodents then placed in the chamber with the cue.

The understanding of the role of cholinergic neurons in regulation of dopamine-related mental illnesses like substance-abuse also contributes insights into depressive and anxiety disorders. If the same pathway implicated in cue-induced drug-seeking were involved in depressive and anxious behaviors, then increasing cholinergic activity should increase pro-depressive behavior.

Addy’s experiment yielded exactly these results, opening up new areas to be further researched to improve the treatment of mood disorders.

Post by Sarah Haurin

 

How We Know Where We Are

The brain is a personalized GPS. It can keep track of where you are in time and space without your knowledge.

The hippocampus is a key structure in formation of memories and includes cells that represent a person’s environment.

Daniel Dombeck PhD, and his team of researchers at Northwestern University have been using a technique designed by Dombeck himself to figure out how exactly the brain knows where and when we are. He shared his methods and findings to a group of researchers in neurobiology at Duke on Tuesday.

Domeck and his lab at Northwestern are working at identifying exactly how the brain represents spatial environments.

The apparatus used for these experiments was adapted from a virtual reality system. They position a mouse on a ball-like treadmill that it manipulates to navigate through a virtual reality field or maze projected for the mouse to see. Using water as a reward, Dombeck’s team was able to train mice to traverse their virtual fields in a little over a week.

In order to record data about brain activity in their mice as they navigated virtual hallways, Dombeck and his team designed a specialized microscope that could record activity of single cells in the hippocampus, a deep brain structure previously found to be involved in spatial navigation.

The device allows researchers to observe single cells as a mouse navigates through a simulated hallway.

Previous research has identified hippocampal place cells, specialized cells in the hippocampus that encode information about an individual’s current environment. The representations of the environment that these place cells encode are called place fields.

Dombeck and his colleague Mark Sheffield of the University of Chicago were interested in how we encode new environments in the hippocampus.

Sheffield studied the specific neural mechanisms behind place field formation.

After training the mice to navigate in one virtual environment, Sheffield switched the virtual hallway, thus simulating a new environment for the mouse to navigate.

They found that the formation of these new place cells uses existing neural networks initially, and then requires learning to adapt and strengthen these representations.

After identifying the complex system representing this spatial information, Dombeck and colleagues wondered how the system of representing time compared.

Jim Heys, a colleague of Dombeck, designed a new virtual reality task for the lab mice.

In order to train the mice to rely on an internal representation of passing time, Heys engineered a door-stop task, where a mouse traversing the virtual hallway would encounter an invisible door. If the mouse waited 6 seconds at the door before trying to continue on the track, it would be rewarded with water. After about three months of training the mice, Heys was finally able to collect information about how they encoded the passing of time.

Heys indentified cells in the hippocampus that would become active only after a certain amount of time had passed – one cell would be active after 1 second, then another would become active after 2 seconds, etc. until the 6-second wait time was reached. Then, the mouse knew it was safe to continue down the hallway.

When comparing the cells active in each different task, Dombeck and Heys found that the cells that encode time information are different from the cells that encode spatial information. In other words, the cells that hold information about where we are in time are separate from the ones that tell us where we are in space.

Still these cells work together to create the built-in GPS we share with animals like mice.

By Sarah Haurin

Long-Term Study Sees the Big Picture of Cannabis Use

Seventy percent of the United States population will have tried marijuana by the age of 30. As the debate on the legalization of the most commonly used illicit drug continues throughout the country, researchers like William Copeland, PhD, and Sherika Hill, PhD, from the Duke Department of Psychiatry and Behavioral Sciences are interested in patterns of marijuana use and abuse in the first 30 years of life.

Marijuana is the most commonly used illicit drug.

The Great Smoky Mountain Study set out in 1992 to observe which factors contributed to emotional and behavioral problems in children growing up in western North Carolina. The study included over 1,000 children, including nearly 400 living on the Cherokee reservation. In addition to its intended purpose, the data collected has proven invaluable to understanding how kids and young adults are forming their relationship with cannabis.

The Great Smoky Mountains Study collected extensive medical and behavioral research from 11 counties in western North Carolina.

Using the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) and patterns of daily use of the drug, Copeland and Hill found some unsurprising patterns: peak use of the drug is during young adulthood (ages 19-21), when kids are moving out of the home to college or to live alone.

But while most people adjust to this autonomy and eventually stop their usage of the drug, a small percentage of users (7%) keep using into their adulthood. Hill and Copeland have observed specific trends that apply both to this chronic user group as well as an even smaller percentage of users (4%) who begin using at a later stage in life than most people, termed the delayed-onset problematic users.

Looking at the demographics of the various types of users, Hill and Copeland found that males are twice as likely to engage in marijuana use to any extent than females. Of those who do use the drug, African Americans are five times more likely to be delayed-onset users, while Native Americans are twice as likely to decrease their use before it becomes problematic.

For both persistent and delayed-onset problematic users, family instability during childhood was 2-4 times more likely than in non-problematic users.

Persistent users were more likely to have endured anxiety throughout childhood, and delayed-onset users were more likely to have experienced some kind of trauma or maltreatment in childhood than other types of users.

The identification of these trends could prove a vital tool in predicting and preventing marijuana abuse, and the importance of this understanding is evidenced in the data collected that elucidates outcomes of marijuana use.

Looking at various measures of social and personal success, the team identified patterns with a resounding trend: recent use of marijuana is indicative of poorer outcomes. Physical health and financial or educational outcomes displayed the worst outcomes in chronic and delayed-onset users. Finally, criminal behavior was increased in every group that used; in other words, regardless of the extent of use, every group with use of marijuana fared worse than the group that abstained.

The results of Copeland and Hill’s work has important implications as legislators debate the legalization of marijuana. While understanding these patterns of use and their outcomes can provide useful insight on the current patterns of usage, decriminalization will certainly change the way marijuana is manufactured and consumed, and will thus also affect these patterns.
By Sarah Haurin

Creative Solutions to Brain Tumor Treatment

Survival rates for brain tumors have not improved since the 1960s; NIH Image Gallery.

Invasive brain tumors are among the hardest cancers to treat, and thus have some of the worst prognoses.

Dean of the Pratt School of Engineering, Ravi Bellamkonda, poses for his portrait inside and outside CIEMAS.

Displaying the survival rates for various brain tumors to the Genomic and Precision Medicine Forum on Thursday, Oct. 26, Duke professor Ravi Bellamkonda noted, “These numbers have not changed in any appreciable way since the 1960s.”

Bellakonda is the dean of the Pratt School of Engineering and a professor of biomedical engineering, but he is first a researcher. His biomedical engineering lab is working toward solutions to this problem of brain tumor treatment.

Unlike many other organs, which can sacrifice some tissue and remain functional, the brain does not perform the same way after removing the tumor. So a tumor without clearly defined boundaries is unsafe to remove without great risk to other parts of the patient’s brain, and in turn the patient’s quality of life.

Bellakonda hypothesized that brain tumors have characteristics that could be manipulated to treat these cancers. One key observation of brain tumors’ behavior is the tendency to form along white matter tracts. Put simply, tumors often spread by taking advantage of the brain’s existing structural pathways.

Bellakonda set out to build a device that would provide brain tumors a different path to follow, with the hope of drawing the tumor out of the brain where the cells could be killed.

The results were promising. Tests on rats and dogs with brain tumors showed that the device successfully guided out and killed tumor cells. Closer examination revealed that the cells killed were not cells that had multiplied as the tumor grew into the conduit, but were actually cells from the primary tumor.

The Bellamkonda lab’s device successfully guided and killed brain tumors in rats.

In addition to acting as a treatment device, Bellakonda’s device could be co-opted for other uses. Monitoring the process of deep brain tumors proves a difficult task for neurooncologists, and by bringing cells from deep within the tumor to the surface, this device could make biopsies significantly easier.

Although the device presents promising results, Bellakonda challenged his lab to take what they have learned from the device to develop a less invasive technique.

Another researcher in the Bellakonda lab, Tarun Saxena, engaged in research to utilize the body’s natural protection mechanisms to contain brain tumors. Creating scar tissue around tumors can trick the brain into treating the tumor as a wound, leading to immunological responses that effectively contain and suppress the tumor’s growth.

Visiting researcher Johnathan Lyon proposed utilizing electrical fields to lead a tumor to move away from certain brain regions. Moving tumors away from structures like the pons, which is vital for regulation of vital functions like breathing, could make formerly untreatable tumors resectable. Lyon’s 3D cultures using this technique displayed promising results.

Another Bellakonda lab researcher, Nalini Mehta, has been researching utilizing a surprising mechanism to deliver drugs to treat tumors throughout the brain: salmonella. Salmonella genetically engineered to not invade cells but to easily pass through the extracellular matrix of the brain have proven to be effective at delivering treatment throughout the brain.

While all of these therapies are not quite ready to be used to treat the masses, Bellakonda and his colleagues’ work presents reasonable hope of progress in the way brain tumors are treated.

By Sarah Haurin

Piloting Aviation Mental Healthcare

With more than 100,000 flights taking off per day, the safety of air travel is a far-reaching issue.

Air travel remains one of the safest forms of transportation, but are there things we can do to make it safer?

While air travel is by far the safest method of transportation — you are more likely to die from a car crash or even a shark attack than from an airplane crash — accidents do happen and can result in highly publicized fatalities.

Chris Kenedi is working with the ICAO to improve treatment of mentally ill pilots.

Auckland Hospital internist and psychiatrist Chris Kenedi, MD, MPH, is working with the International Civil Aviation Organization (ICAO) to improve safety of air travel by focusing on an issue that is usually only questioned in instances of tragedy: the mental health of pilots.

While screening procedures do currently exist, they are not enough for the extent of risk factors that are present in the pilot population.
Being a pilot is a high-stress job. It involves long hours, separation from family, and irregular sleep schedules, all of which can contribute to or exacerbate mental conditions.

Many pilots experiencing symptoms are unwilling to ask for help, because admitting mental illness can lead to a pilot’s license being revoked, which would not only affect financial circumstances but also be felt as a loss of identity.

Although data regarding aviation mental health is sparse, what is available suggests  mental health issues are among the greatest contributing factors to suicide and homicide-suicide incidents of plane accidents.

When Kenedi completed a systematic review of all data on the mental health of pilots and the current standard procedures, he found a deeply flawed system. Case studies of crashes caused by suicidal pilots showed that psychiatrists cleared them for flight even after episodes indicating a much deeper psychological imbalance.

One pilot who drove his car into a barrier, attempted to steal the car of a woman trying to help him, and slit his wrists so deeply that he required two years of rehabilitation before regaining all of his mobility, was diagnosed with a general anxiety disorder and cleared to fly without proper treatment.

In order to prevent further grave oversights, Kenedi suggests requiring the psychiatrist who assesses a pilot’s ability to fly to be separate from the treating psychiatrist. This separation prevents the assessing psychiatrist from having his or her judgement confounded by a relationship with the patient and thus becoming an advocate rather than an impartial assessor.

Kenedi said that alcohol and substance abuse treatments for pilots have been effective, however. Rather than relying on random drug and alcohol tests to disqualify impaired pilots, the system provides non-judgmental treatment and an opportunity to return to piloting.

Kenedi recommends a shift to treating mental illness in pilots in a similar way, so that individuals are not afraid to step forward and ask for help. Educating mental healthcare providers is also important, so that pilots are receiving the best care possible.

With proper resources and treatment, pilots with mental health concerns should be able to maintain their identity as pilots while gaining renewed resilience and support through the mental health system. This shift would hopefully help to prevent some of the small amount of air travel accidents that occur because of pilot issues.

By Sarah Haurin

 

How Climate Change Limits Educational Access

Regions with agricultural economies suffer greatly from climate change.

The effects of climate change can creep into nearly every aspect of life in heavy-hit areas. They may even limit children’s access to education, says Nicholas School of the Environment graduate Heather Randell.

“Investments in education are an important pathway out of poverty, yet lack of access remains a barrier,” Randall said in a presentation to Nicholas School students and faculty.

Randell became interested in the relationship between climate change and education when she visited Ethiopia before pursuing her doctorate. She noticed many school-age kids were working rather than pursuing an education, and began to wonder what factors influence children’s time use.

Heather Randell PhD is a sociologist and demographer for the National Socio-Environmental Synthesis Cener (SESYNC).

Although the UN’s Millennium Development Goals and Beyond 2015 aimed to ensure universal primary education for all school-age children, 20 percent of children in Sub-Saharan Africa were still out of school in 2017.

Using data from the Ethiopian Rural Household Survey, Randell found that when children experience milder temperatures and more ample rainfall during their early life, they are more likely to stay in school longer. This trend can be attributed to the close ties between the economy and climate in agricultural areas like those in rural Ethiopia.

Agricultural economies are inherently dependent on temperature and rainfall. Increased temperature and decreased rainfall lower crop yield, which in turn decreases individual families’ incomes.

Children in Ethiopia are less likely to continue their education if they experienced hotter temperatures and less rainfall in their early childhood.

With less disposable income, families are more likely to spend their money on necessities like food rather than on schooling fees. Families are also more likely to pull children out of school so kids can work and contribute to the diminished family income.

After finding these patterns in Ethiopia, Randell expanded her research to include regions in the tropics, including Central America, the Caribbean, South America, East Africa, West Africa and Southeast Asia. Each of these regions has variations in their typical rainfall and temperatures, but all are inherently susceptible to climate change because of their location near the equator.

From her research in Ethiopia, Randell found two mechanisms by which climate change influences educational outcomes.

Comparing standardized census and climate data from these regions, Randell found a similar pattern, with increased temperature and changes in rainfall being associated with decreased educational outcomes.

This study also found that climate change and its negative effects often outweigh typical advantages that improve educational access, such as parents who have had a longer schooling.

Randell concluded her talk by stating that true and lasting change to educational accessibility will only be brought about by policy change. School must be less expensive and more accessible, and more importantly, livelihood diversification must be taught and encouraged. Families must learn how to generate income in ways other than agriculture so that their income and familial decisions are more resilient to climate variability.

By Sarah Haurin

Rare Cancers and Precision Medicine in Southeast Asia

Data collected through genomics research is revolutionizing the way we treat cancer. But a large population of cancer patients are being denied the benefits of this research.

Patrick Tan MD, PhD is a professor of cancer and stem cell biology at Duke-NUS Medical School in Singapore.

In 2016, less than one percent of all the existing genomic data came from the 60% of the world population living outside of the US, Europe, and Japan. Furthermore, 70% of patients who die from cancer this year will come from Asia, Africa and Central and South America.

Patrick Tan, M.D., Ph.D., and the Duke-National University of Singapore (Duke-NUS) Medical School are key players in an effort to rectify this discrepancy, specifically as it exists in Southeast Asia.

In his talk, sponsored by the Duke Center for Applied Genomics and Precision Medicine, Tan focused specifically on his work in northeast Thailand with cholangiocarcinoma (CCA), or bile duct cancer.

Liver fluke

Liver flukes like this are parasites of fish that migrate to human hosts who eat the fish raw, leading to a form of bile duct cancer.

While CCA is rare in most of the world, it appears at 100 times the global rate in the region of Thailand where Tan and his colleagues work. Additionally, CCA in this region is of a separate and distinct nature.

CCA in this region is linked with a parasitic infection of the bile ducts called a liver fluke.  Residents of this area in Thailand have a diet consisting largely of raw fish, which can be infected by the liver fluke and transmitted to the person who eats the fish.

Because of the poverty in this area, encouraging people to avoid eating raw fish has proven ineffective. Furthermore, healthcare is not readily available, so by the time most patients are diagnosed, the disease has progressed into its later and deadly stage.

The life cycle of liver flukes. (Graphic U.S. Centers for Disease Control)

Tan’s genomic research has discovered certain factors at the gene level that make liver-fluke positive CCA different from other CCA. Thus genomic data specific to this population is vital to improve the outcomes of patients with CCA.

Duke-NUS Precision Medicine (PRISM) has partnered up with the National Heart Research Institute Singapore (NHRIS) in SPECTRA, a program designed to create a database of genomic data from the healthy Asian population. SPECTRA is sequencing the genomes of 5,000 healthy Asians in order to create a baseline to which they can compare the genomes of unhealthy individuals.

These and other programs are part of a larger effort to make precision medicine, or healthcare tailored to an individual based on factors like family history and genomic markers, accessible throughout southeast Asia.

By Sarah Haurin

 

Disaster Plans and the Mentally Ill

Houston, Miami, San Juan — Category 5 hurricanes, the most destructive storm systems, have made a record-breaking 6 landfalls this year. This represents a quarter of the total category 5 hurricane landfalls that the Atlantic has seen since 1851.

With statistics like these, disaster relief plans are becoming more important than ever. But do these plans do enough for marginalized groups, specifically the mentally ill?

Allan K. Chrisman, M.D., believes more can be done. As a career psychiatrist who has been deployed by the Red Cross in the aftermath of storms like Katrina and Matthew, Chrisman has seen and experienced the importance of including the mentally ill in disaster relief plans.

At his talk to physicians in Duke’s Hospital on Sept. 28, Chrisman, an emeritus  professor at Duke, highlighted specific aspects of disaster relief that are not doing enough for the one in four U.S. adults suffering from mental illness each year.

According to Chrisman, this part of the population is often less prepared for impending storms. When storms do hit, existing symptoms can be exacerbated, or new symptoms can appear.  Disruption of routine, inconsistency of taking medication and the overall stress that comes with emergencies all contribute to this exacerbation of mental illness.

While the Red Cross has an “everyone is welcome,” policy for their shelters, not being able to identify the needs of the mentally ill seeking sanctuary limits the organization’s ability to help. As a deployed psychiatrist, Chrisman worked with displaced mentally ill people to ensure they continued to get the care they needed even during the stress of a weather emergency.

One tool used by Chrisman and his colleagues to help these groups is the C-MIST framework. This system categorizes “functional-based needs” based on communication, maintaining health, independence, service and support, and transportation. It seeks to ensure not only that individuals are being given an option for a safe space in the wake of emergencies, but also that these spaces offer them the specific services they require.

Chrisman emphasized the need “to provide round-the-clock access to qualified mental health resources.”

He said that by following these inclusive protocols, disaster relief programs can do even more to protect the most vulnerable parts of the population.

By Sarah Haurin

Happy Patients, Healthy Lungs

Lung-shaped leaves

Evaluating a patient’s mental health before and after lung transplant surgery can help improve long-term outcomes. Source: tikyon, Flickr.

Diseases like Chronic Obstructive Pulmonary Disease (COPD) and Cystic Fibrosis (CF) are hard to treat. Lung transplant is important option for people who do not benefit from other treatments, and understanding the outcomes for these patients is crucial.

Patrick Smith, PhD, a clinical psychologist at Duke Hospital, shared his research into predictors for outcomes of lung transplant with a group of transplant physicians and surgeons at the Duke Hospital on Sept. 14.

“Patients receive transplants to live longer and to feel better,” Smith said.

Focus on the first goal has increased the median survival time after a lung transplant to six years. But Smith began his research because of an interest in the second goal.

An incredibly complex, long, and difficult procedure, transplants require extensive testing and therapies before a patient enters the operating room (OR). Among the pre-operative testing is a mental health assessment to determine if any psychological issues exist that could make recovery more difficult. Mental health issues can affect adherence, or a patient’s commitment to continuing the prescribed post-op medication after release from the hospital.

Smith’s research found that some of these tests can be incredibly useful at predicting outcomes not previously explored; patients who show cognitive impairments before surgery were found to be more likely to fall victim to delirium, a post-operative state of confusion and psychosis that has been linked to an increased risk of complications and death.

While acknowledging the usefulness of pre-operative testing, Smith also pointed out the inadequacy of this model. Failing to continue psychological assessments after the surgery and throughout the recovery means that doctors are missing important clues that could indicate how well patients will recover.

Through his research, Smith has found that the presence of depressive symptoms after transplant is actually a much more useful and accurate tool for predicting risk of mortality than symptoms exhibited before surgery.  

This point is strengthened by a previous study that found that successful treatment of depressive symptoms in liver transplant patients reduced the mortality rate of depressive patients to that of their non-depressive counterparts.

These results are promising for the possibility of improving transplant outcomes; by valuing and treating both pre-operative and post-operative signs of risk, doctors can improve the outcomes for their patients and ensure the limited supply of organs is being used in the best and most successful way possible.

Post by Sarah Haurin

 

 

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