While the effects of acute stroke have been widely studied, brain damage during the subacute phase of stroke has been a neglected area of research. Now, a new study by the University of South Florida reports that within a week of a stroke caused by a blood clot in one side of the brain, the opposite side of the brain shows signs of microvascular injury.
Stroke is a leading cause of death and disability in the United States, and increases the risk for dementia.
“Approximately 80 percent of strokes are ischemic strokes, in which the blood supply to the brain is restricted, causing a shortage of oxygen,” said study lead author Svitlana Garbuzova-Davis, PhD, associate professor in the USF Department of Neurosurgery and Brain Repair. “Minutes after ischemic stroke, there are serious effects within the brain at both the molecular and cellular levels. One understudied aspect has been the effect of ischemic stroke on the competence of the blood-brain barrier and subsequent related events in remote brain areas.”
Using a rat model, researchers at USF Health investigated the subacute phase of ischemic stroke and found deficits in the microvascular integrity in the brain hemisphere opposite to where the initial stroke injury occured.
The study was published in the May 10, 2013 issue of PLOS One.
The USF team found that “diachisis,” a term used to describe certain brain deficits remote from primary insult, can occur during the subacute phase of ischemic stroke. The research discovered diachisis is closely related to a breakdown of the blood-brain barrier, which separates circulating blood from brain tissue.
In the subacute phase of an ischemic stroke, when the stroke-induced disturbances in the brain occur in remote brain microvessels, several areas of the brain are affected by a variety of injuries, including neuronal swelling and diminished myelin in brain structures. The researchers suggest that recognizing the significance of microvascular damage could make the blood-brain barrier (BBB) a therapeutic “target” for future neuroprotective strategies for stroke patients.
The mechanisms of BBB permeability at different phases of stroke are poorly understood. While there have been investigations of BBB integrity and processes in ischemic stroke, the researchers said, most examinations have been limited to the phase immediately after stroke, known as acute stroke. Their interest was in determining microvascular integrity in the brain hemisphere opposite to an initial stroke injury at the subacute phase.
Accordingly, this study using rats with surgically-simulated strokes was designed to investigate the effect of ischemic stroke on the BBB in the subacute phase, and the effects of a compromised BBB upon various brain regions, some distant from the stroke site.
“The aim of this study was to characterize subacute diachisis in rats modeled with ischemic stroke,” said co-author Cesar Borlongan, PhD, professor and vice chairman for research in the Department of Neurosurgery and Brain Repair and director of the USF Center for Aging and Brain Repair. “Our specific focus was on analyzing the condition of the BBB and the processes in the areas of the brain not directly affected by ischemia. BBB competence in subacute diachisis is uncertain and needed to be studied.”
Their findings suggest that damage to the BBB, and subsequent vascular leakage as the BBB becomes more permeable, plays a major role in subacute diachisis.
The increasing BBB permeability hours after the simulated stroke, and finding that the BBB “remained open” seven days post-stroke, were significant findings, said Dr. Garbuzova-Davis, who is also a researcher in USF Center for Aging and Brain Repair. “Since increased BBB permeability is often associated with brain swelling, BBB leakage may be a serious and life-threatening complication of ischemic stroke.”
Another significant aspect was the finding that autophagy — a mechanism involving cell degradation of unnecessary or dysfunctional cellular components —plays a role in the subacute phase of ischemia. Study results showed that accumulation of numerous autophagosomes within endothelial cells in microvessels of both initially damaged and non-injured brain areas might be closely associated with BBB damage.
Autophagy is a complex but normal process usually aimed at “self-removing” damaged cell components to promote cell survival. It was unclear, however, whether the role of autophagy in subacute post-ischemia was promoting cell survival or cell death.
More than 30 percent of patients who survive strokes develop dementia within two years, the researchers noted.
“Although dementia is complex, vascular damage in post-stroke patients is a significant risk factor, depending on the severity, volume and site of the stroke,” said study co-author Dr. Paul Sanberg, USF senior vice president for research and innovation. “Ischemic stroke might initiate neurodegenerative dementia, particularly in the aging population.”
The researchers conclude that repair of the BBB following ischemic stroke could potentially prevent further degradation of surviving neurons.
“Recognizing that the BBB is a therapeutic target is important for developing neuroprotective strategies,” they said.
Neurons that can multitask greatly enhance the brain’s computational power, study finds
May 20, 2013 by Anne Trafton in Neuroscience
An artist’s impression depicting a network of neurons of the nervous system. Credit: MAURIZIO DE ANGELIS/WELLCOME IMAGES
Over the past few decades, neuroscientists have made much progress in mapping the brain by deciphering the functions of individual neurons that perform very specific tasks, such as recognizing the location or color of an object.
However, there are many neurons, especially in brain regions that perform sophisticated functions such as thinking and planning, that don’t fit into this pattern. Instead of responding exclusively to one stimulus or task, these neurons react in different ways to a wide variety of things […]
When the American Psychiatric Association releases its newDiagnostic and Statistical Manual of Mental Disorders— DSM-5 — this weekend, lots of journalists and commentators will refer to it as “psychiatry’s bible.”
That’s a term that makes the manual’s authors and other mental experts cringe.
“Bible implies that it’s been handed down by some deity as the absolute truth,” says Michael First, a psychiatrist at Columbia University who’s had a hand in the past two revisions of the DSM. ”We don’t consider this to be a bible. It’s a guidebook.”
Dr. Thomas Insel, director of the National Institute of Mental Health, also wants people to know the DSM isn’t some sacred text. “It’s a dictionary, not a bible,” he says.
The DSM has taken on biblical proportions over the years because its list of several hundred disorders is often used to decide whether a particular behavior is abnormal and insurance will cover a problem. DSM-5, for example, has provoked lots of debate about new diagnoses like Binge Eating Disorder or Disruptive Mood Dysregulation Disorder in children.
But insurance coverage and defining what’s normal are not why theDSM was created. It was created to solve a communication problem.
Before DSM-III came along in 1980, “It was really chaotic,” Insel says. “We had no common language” for describing mental disorders. The new manual provided clear definitions for the first time, he says, so that “when one person says major depressive disorder another person will know what that is.”
Revisions since then have updated those definitions and added or eliminated diagnoses based on the latest research, First says. “TheDSM is a synthesis of the best knowledge at this moment in time,” he says. “So DSM-5 is the culmination of research in the past 20 years.”
That makes the DSM ”a tool used by clinicians to take care of patients,” not a bible, First says.
Insel adds that the DSM only becomes a problem when mental health professionals forget that and start “looking at the manual instead of listening to their patients. That’s never a good outcome.”
Most of us don’t ponder our pulses outside of the gym. But doctors use the human pulse as a diagnostic tool to monitor heart health.
Zhenan Bao, a professor of chemical engineering at Stanford, has developed a heart monitor thinner than a dollar bill and no wider than a postage stamp. The flexible skin-like monitor, worn under an adhesive bandage on the wrist, is sensitive enough to help doctors detect stiff arteries and cardiovascular problems.
There is a lot of data available about how physicians perceive and use digital technologies. Yet, less is known about how their perceptions and use patterns compare to other health providers. In addition, there is very little research on how things change when providers are passively observed utilizing the Web to research and consume medical information.
This infographic features research from a stand-alone digiheatlh pulse study conducted between late 2011 and early 2012. It explores the differences and similarities between what providers recall versus the reality of their online experiences. This infographic was published in Summer 2012.
Source: m.washingtonpost.com[Pediatric cardiologist Laura Olivieri of Children’s National Medical Center displays a heart model created by a 3-D printer. (Amanda Voisard/For The Washington Post)] via MediaMed
To help solve challenging cardiac problems, doctors at Children’s press ‘print’
By Adrienne LaFrance, Published: MAY 13, 2:39 PM ET. The Washington Post.
It may sound like something out of science fiction, but doctors at Children’s National Medical Center are making hearts. Not actual hearts, but three-dimensional synthetic models churned out by what looks like an ordinary printer.
The only one of its kind at a Washington area hospital, the printer uses data from individual patients to replicate the organs of those individuals, reflecting their particular intricacies and deformities. The device synthesizes images from CT scans or ultrasounds, translating that information into thin layers of plastic that are stacked until they form a three-dimensional object.
The technology, pediatric cardiologist Laura Olivieri says, “is amazing.”