Traumatic Brain Injury, A New Point of View
Alternative Brain Scanning Technology May Aid Diagnosis
Researchers have found new evidence linking losses in memory and attention to subtle forms of brain damage following mild traumatic brain injury (TBI), which may eventually help in diagnosing when a routine concussion might lead to lasting cognitive problems. TBI affects more than 500,000 Americans each year and over 70 percent of these injuries are considered "mild," usually due to a concussion. Fifteen to 30 percent of these patients will suffer long-term impairments of memory and attention. The findings are published online and in the December issue of the journal BRAIN.
Following a head injury, patients who experience a concussion often show no signs of damage in a traditional CT or MRI scan, pass a basic neurological exam, and are then sent home with no additional treatment or follow-up. However, many such patients continue to report symptoms weeks and even months later, such as loss of concentration or memory loss — termed post-concussive syndrome.
The researchers studied diffusion tensor imaging (DTI), an advanced type of MRI scan that allows experts to view the microscopic motion of water molecules within the brain's white matter, the tissue that connects and allows communication between different brain centers. The group found that injury was visible in the subjects' memory and attention networks of the brain, but not visible via conventional MRI scans. The team, including researchers from Weill Cornell Medical College and University of California at San Francisco, identified two particular white-matter tracts, one strongly associated with attention and the other memory, in the brains of normal adults and adults with mild TBI.
Dr. Bruce McCandliss, corresponding author and associate professor of psychology in psychiatry at Weill Cornell Medical College, and co-first authors Sumit Niogi of Weill Cornell and Dr. Pratik Mukherjee of UCSF believe that these findings might be the first step toward clinical trials that will determine whether DTI may one day be used for early and accurate diagnosis in patients following TBI.
Since DTI is conducted with an MRI scanner, no additional equipment or cost is needed to collect such data. However, the researchers say that analyzing and interpreting the data is more complex, and tools for clinical diagnosis are still under development.
Contributing authors include Dr. Jamshid Ghajar, Dr. Minah Suh and Rachel Kolster, from Weill Cornell Medical College; and Dr. Geoffrey T. Manley and Hana Lee, from the University of California, San Francisco. The work was funded by a grant from the J.S. McDonnell Foundation.
Herb Studied for Enlarged Prostate
Saw Palmetto Therapeutic for Urinary Symptoms?
Physician-scientists are studying an herbal supplement that might aid in reducing the symptoms of an enlarged prostate in men. Recent figures show that benign prostatic hyperplasia (BPH) occurs in an estimated 50 percent of men over the age of 50 and in 75 percent of men 80 and older.
The research team, led by Dr. Steven A. Kaplan, professor of urology at Weill Cornell Medical College and attending urologist at NewYork-Presbyterian Hospital/Weill Cornell, will study the affects of using saw palmetto extract compared to a placebo, with the hope of reducing the symptoms of BPH. Symptoms include difficulty starting a urine stream (hesitancy and straining), decreased strength of the urine stream (weak flow), feeling that the bladder is not completely empty, an urge to urinate again soon after urinating and pain during urination (dysuria).
It is theorized that compounds called phytoesterols, found in saw palmetto, might prevent prostate enlargement. Experts believe that prostate swelling may be caused by a rise in dihydrotestosterone (DHT) — a testosterone derivative involved in prostate growth — over a male's lifespan, especially during middle age. Scientists are unclear as to what causes the hormone to rise with time. However, escalating estrogen within the body has been correlated with, but has not been proven to be, directly promoting BPH. Like a basketball player blocking a shot from going into a basket, phytoesterols in saw palmetto might block natural estrogen from binding to receptors in the body.
Newly Discovered Protein May Help Explain Tuberculosis' Resiliency
Experts Find Another Reason Why the Bacterium Is So Nasty
Weill Cornell scientists have located a protein produced by the tuberculosis bacterium that may tell researchers more about how the invader lives so resiliently inside of the body. Dr. Benjamin Gold, working with Dr. Carl Nathan, chairman of microbiology and immunology at Weill Cornell Medical College and their colleagues, located a protein called mycobacterial metallothionein (MymT), which acts like a shield to protect the tuberculosis bacterium from the body's natural defenses.
The tuberculosis bacterium lurks within cells called macrophages — immune system cells that bombard harmful microbes with a soup of chemicals, including nitric oxide. The researchers believe that the newly discovered protein helps the bacterium resist a newly discovered action of nitric oxide, thus allowing the infection to stay strong within the body. The Weill Cornell scientists discovered nitric oxide can liberate copper from proteins within the bacterium, and may also reduce it from a relatively harmless form to lethal form. The new protein, MymT, binds the copper to protect the bacterium from being poisoned by the metal.
All the genetic information in the tuberculosis organism was sequenced in 1998. Yet the gene encoding MymT was overlooked until now because of its very small size and the novel way it encodes the protein. Thus, this study suggests that there may be other genes in bacterial pathogens that contribute to their potential to cause disease, but which have otherwise been overlooked, including relatives of MymT.
The study is published in a recent issue of the journal Nature Chemical Biology.
