abuse

New findings from a long-term investigation indicate that child abuse leads to a potentially dangerous disruption of the body's stress response in adulthood। Previously abused individuals display elevated blood concentrations of inflammatory substances that fight infections and repair damaged tissue, say psychologist Andrea Danese of King's College London and her colleagues। http://louisdjdsheehan.blogspot.com

Prior research has linked persistent inflammation to heart disease, diabetes, and chronic lung disease। http://louisdjdsheehan.blogspot.com

Danese's group analyzed data on 866 people born in Dunedin, New Zealand, between April 1972 and March 1973. Volunteers underwent medical and psychological tests at regular intervals from ages 3 to 32.

Home observations and reports from parents and children established that 83 participants had experienced abuse or serious traumas by age 11. These incidents included maternal rejection, physical abuse, sexual abuse, and two or more changes in a child's primary caregiver.

At age 32, previously abused individuals exhibited markedly higher concentrations of two inflammatory substances—C-reactive protein and fibrinogen—than their unabused peers did, the researchers report in the Jan. 23 Proceedings of the National Academy of Sciences. Abused volunteers' blood also carried elevated numbers of infection-fighting white blood cells.

Especially high concentrations of inflammatory substances appeared in participants who had suffered severe abuse as children, the investigators say. The findings held true when the scientists accounted for other inflammation-boosting factors, including low birth weight and use of alcohol and cigarettes.

reward

Dopamine conducts a frenzied song of craving at one end of a tiny brain region and a panic-stricken hymn at the other। Depending on where along the length of the region the neurotransmitter is triggered, it elicits emotions ranging from desire to disgust, a new study shows। http://louis1j1sheehan1esquire1.blogspot.com

“The roles [of dopamine] may be partitioned, and perhaps defined, by anatomy,” comments Emily Hueske, a neuroscientist at the Massachusetts Institute of Technology.

With the recent study, researchers have come one step closer to explaining how dopamine performs a spectrum of functions. Dopamine interacts with spatially coded signals so that its output varies from one end of a brain region to the other, the team reports in the July 9 Journal of Neuroscience। http://louis1j1sheehan1esquire1.blogspot.com

In the long-term, drugs might be developed to locally treat various dopamine-mediated disorders such as drug addiction, obsession, obesity and anxiety.

Kent Berridge, a neuroscientist and psychologist at the University of Michigan in Ann Arbor, and his colleagues set out to understand how dopamine could lead to desire for a reward, and then turn around and cause fear, pain and stress.

Berridge’s team focused on the area of the nucleus accumbens known as the pleasure center in all mammals. The researchers report the effects of tampering with dopamine and another chemical messenger, the glutamate neurotransmitter, along the length of the nucleus accumbens of rats.

A tiny, localized injection at the front end disrupted glutamate and turned normal rats into binge-eaters. But when researchers injected the same glutamate blocker at the back end of the nucleus accumbens, the rats stopped eating and became fearful — kicking up sand at the bottom of their cages, as wild rodents are wont to do when a snake or a scorpion is in their midst, Berridge says.

When both dopamine and glutamate were blocked, the rats did not display the extreme behaviors। In nature, the interaction between the two may guide how a rat responds to signals from the environment। Glutamate may bring in information from the outside world, and dopamine may act on that information, Berridge suggests. http://louis1j1sheehan1esquire1.blogspot.com

Because the injections only blocked glutamate or dopamine in tiny bits of the nucleus accumbens, the researchers were able to map out a millimeter-by-millimeter gradient of reactions over the region. “The brain cares where you are exactly,” Berridge says.

“This is perhaps a surprise,” says behavioral neuroscientist Richard Palmiter of the University of Washington in Seattle. He’s not shocked about the gradient of dopamine-mediated reactions because desire and dread aren’t completely unrelated. Regardless of how the rat responds to a stimulus, “dopamine is basically saying: ‘Hey, pay attention to your environment’,” he says.

Still, this study shows how motivation for a reward can turn to fear within a single structure, Berridge says.

The researchers describe the gradient as a keyboard, with keys going from desire to fear. The minute keyboard gradient found in the rats may translate into a slightly larger, centimeter-by-centimeter keyboard in humans’ nucleus accumbens. Berridge speculates that the boundaries of “keys” are skewed in people with certain disorders, such that a sensation produces more pleasure than it should in an addict or too much fear in schizophrenic patients.

Once scientists know what underlies the front-to-back gradient, drugs could be refined to more accurately treat separate disorders, says Charlotte Boettiger, a behavioral neuroscientist at the University of North Carolina at Chapel Hill. It may be years before those treatments are developed, however. “We don’t presently have a way to target drugs to one part or the other.”

antibiotic

The threat of antibiotic resistance is nothing to scoff at: The World Health Organization predicts (pdf) that some diseases, including malaria, tuberculosis, and pneumonia, could have “no effective therapies within the next 10 years.” http://louis_j_sheehan.today.comIndeed, 70 percent of hospital-acquired bacterial infections in the United States—which kill 90,000 Americans a year—are resistant to at least one drug, according to the Centers for Disease Control and Prevention. But scientists are working hard to find more potent antibiotics, and they are uncovering them in the strangest of places, from alligators’ veins to cholesterol drugs.

1. Gator Blood
Alligators fight off infections far better than humans do, perhaps due to an adaptation that promotes rapid wound healing. Recent lab tests show that tiny amounts of alligator blood extract—some scientists call it alligacin—kill many microbes, including Methicillin-resistant Staphylococcus aureus (MRSA), and help fight HIV.

2. Frog Skin
Last year Italian scientists isolated short proteins called antimicrobial peptides from frog skin and tested them on strains of multidrug-resistant bacteria. The peptides not only killed bacteria directly, but also ramped up the host immune system to help clear infections more quickly.

The peptides are so fragile that they rapidly break down in blood; the researchers nevertheless found one that killed five bacterial species in the presence of blood. Among the affected microorganisms were three that commonly cause deadly hospital-acquired infections, including Staphylococcus aureus and two emerging bacterial pathogens, Stenotrophomonas maltophilia and Acinetobacter baumannii, that are a growing cause of infections in hospital intensive-care units। http://louis_j_sheehan.today.com

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3. Synthetic Molecules
Researchers at Northwestern University recently engineered versions of antimicrobial peptides to make them more resilient. Called peptoids, these synthetic molecules are stronger than natural peptides, last longer in the body, and are cheaper to produce. When the scientists added them to cultures of six bacteria known to cause food poisoning, pneumonia, hospital-acquired infections, and ear and heart infections, the peptoids wiped them all out.

4. Focused phages
If bacteria evolve to become drug resistant, why not subject them to bacteria-fighting microbes, called phages, that evolve along with them? http://louis_j_sheehan.today.comWhen ingested or topically applied, phages cure infections but leave the rest of the body and “good” bacteria alone। So-called phage therapy is widely used in Eastern Europe and is currently undergoing one U।S। clinical trial. Since phages have evolved with their bacterial targets for billions of years, they could solve the problem of antibiotic resistance for good; the downside is that each bacterial strain requires its own tailored phage cocktail, so it could be many years before doctors have a suitably broad range of phages at their disposal.

5. Cholesterol Drugs
MRSA bacteria produce an antioxidant that helps destroy toxic free radicals generated in the infection-fighting process. The antioxidant, scientists found, is produced through a process similar to one used by humans to manufacture cholesterol. Thus, researchers wonder whether cholesterol-lowering compounds might act as a new sort of antibiotic. Mice given the drug and then infected with MRSA had 98 percent less bacteria than mice not given the d