April 3, 2007, 10:49 PM CT

How Lead Exposure Produces Learning Deficits

A study of young adult rats by scientists from the Johns Hopkins Bloomberg School of Public Health provides evidence that explains exactly how exposure to lead during brain development produces learning deficits. The study shows that exposure to levels of lead that are similar to those measured in lead-intoxicated children reduces the birth and survival of new neurons (neurogenesis) in the brain. Lead also alters the normal development of newly born neurons in a part of the brain (hippocampus) known to be important for learning and memory. The study is reported in the March 30, 2007, issue of Neuroscience.

"There was a dogma in neuroscience that you were born with all the neurons you would ever have, but that thinking has changed dramatically in the last 20 years," said Tomás R. Guilarte, PhD, senior author of the study and professor of environmental health sciences at the Johns Hopkins Bloomberg School of Public Health. "The exciting idea is that researchers have discovered ways to increase the number of new neurons, and this may facilitate learning in the hippocampus portion of the brain".

The scientists studied young adult rats, using a group of lead-treated and non-treated (control) rats. When they examined the brains of lead-exposed rats, they observed that fewer neurons were born and those neurons that were born survived for a shorter amount of time and had abnormal development......... Posted by: JoAnn      Read more         Source

April 3, 2007, 10:43 PM CT

Allergic Diseases and Autoimmune Diseases

A new study by scientists at Children's and the University of Washington (UW) identifies a correlation between allergic diseases such as atopic dermatitis, also known as eczema, and autoimmune diseases. The study was reported in the April 1 edition of Nature Immunology.

Approximately 75 percent of autoimmune diseases occur in women, most frequently during the childbearing years. These diseases also comprise a significant portion of chronic childhood disorders. Autoimmune disease refers to a group of more than 80 serious, chronic illnesses including diseases of the nervous, gastrointestinal, and endocrine systems as well as skin and other connective tissues, eyes, blood, and blood vessel. In all of these diseases, the underlying problem is similar-the body's immune system (including B and/or T immune cells) becomes misdirected, attacking the very organs it was designed to protect.

"Our study implies that allergic and inflammatory diseases may actually trigger autoimmune diseases by relaxing the controls that normally eliminate newly produced, self-reactive B cells. This is important because a number of autoimmune diseases are caused by self-reactive antibodies produced by such B cells" said Dr. David Rawlings lead researcher and section head of Immunology at Children's Hospital and the UW......... Posted by: JoAnn      Read more         Source

April 2, 2007, 10:14 PM CT

Primary Medical Care For Children With Autism

Children with autism do not receive the same quality of primary care as children with other special health care needs, as per research from the University of Minnesota Medical School.

A study reported in the Archives of Pediatrics and Adolescent Medicine observed that parents of children with autism were less likely to report that their children received the type of primary care advocated by the American Academy of Pediatrics (AAP) when in comparison to parents of children with other special health care needs. The "medical home model," which is defined by the AAP as accessible, continuous, comprehensive, family-centered, compassionate, culturally effective, and coordinated with specialized services was used as a measure for ideal primary care of children.

"This study shows that children with autism are less likely to receive the type of primary medical care that we hope for all children," says principal investigator Allison Brachlow, M.D., research fellow at the Department of Pediatrics. "With increasing numbers of children diagnosed with autism, it is imperative to understand how to provide optimal care for these children".

Specifically, Brachlow observed that parents of children with autism were less likely to report their childs care was family-centered, comprehensive, or coordinated. For example, parents of children with autism were less likely to report that their childs primary care provider spent adequate time with them, offered understandable explanations, or discussed outside services, such as speech and occupational therapies. Furthermore, parents of children with autism were more likely to report difficulties obtaining subspecialty care, such as referrals to a gastroenterologist or other subspecialty doctor......... Posted by: JoAnn      Read more         Source

March 28, 2007, 10:08 PM CT

Child's play is serious study of cause and effect

It's not child's play to Laura E. Schulz, assistant professor of brain and cognitive sciences at MIT, to figure out what child's play is all about.

Schulz spoke March 21 at an MIT Museum Soap Box event, "Twisting the Lion's Tail: Exploratory Play and Children's Causal Learning".

Soap Box is a series of salon-style, early-evening conversations with researchers and engineers in the news, a public forum for debate about ideas and issues in science and technology.

The theory of cause and effect is fundamental to our understanding of the world. However, despite almost universal agreement that children learn about cause and effect through exploratory play, little is known about how children's play might support accurate causal learning, Schulz said.

"One of the deep mysteries of cognitive science is how we predict the future and how we explain the past and intervene in the present," she said. Causal reasoning even pervades our emotional lives when we speculate about why someone has a certain expression on her face or why a friend or colleague said what he did.

Causation in a nutshell: If you change this, all else being equal, something else changes. From earliest infancy and across all species, action and effect are correlated. Anyone who owns a pet knows that an animal quickly learns that opening a certain food container means dinner is on the way......... Posted by: JoAnn      Read more         Source

March 25, 2007, 8:46 PM CT

Issues In Pediatric Cardiology

Heart problems in children are quite different from those in adults, and four studies presented today at the American College of Cardiologys 56th Annual Scientific Session look at how pediatric heart specialists take different approaches to better understand and manage cardiovascular disease in this population, including insights into fundamental cardiac mechanisms and testing of new procedures. ACC.07 is the premier cardiovascular medical meeting, bringing together heart specialists and cardiovascular specialists to further breakthroughs in cardiovascular medicine.

"Congenital heart disease is one of the most common birth defects seen in the United States today, and it is important we continue supporting research that will improve the diagnosis and therapy of infants, children and young adults with these problems, said Roberta Williams, M.D., of the Children's Hospital of Los Angeles. These studies show how a better understanding of new technologies can save lives and establish a better quality of life for children living with cardiovascular disorders.

Long-term Follow-up of Stents Placed in Infants with Congenital Heart Disease (Presentation Number 1017-27).

Stents have been credited with saving thousands of lives by treating blocked coronary arteries. While the implantation of balloon-expandable stents in infants has been shown to be technically feasible, there is essentially no long-term data showing that this therapy remains effective as an infant grows. In order to determine the benefits of stent implantation in infants, scientists from Miami Childrens Hospital in Florida conducted a retrospective analysis on the earliest consecutive series of infants who underwent stent placement between October 1995 and December 1999......... Posted by: Daniel      Read more         Source

March 22, 2007, 10:37 PM CT

Viral enzyme recruited in fight against ear infection

Parents might one day give their children a weekly therapy with a nasal spray of virus enzymes to prevent them from getting a severe middle ear infection, based on results of a study done in mice by researchers from St. Jude Children's Research Hospital and The Rockefeller University in New York. Such a therapy would kill the disease-causing bacteria without the use of antibiotics, thereby avoiding the problem of antibiotic resistance. A report on this study appears in the recent issue of the online journal "PLoS Pathogens."

Middle ear infection, also called acute otitis media, is an inflammation of the middle ear space that can cause pain, fever, irritability, lack of appetite and vomiting. The middle ear is the space just before the eardrum. About half of all children carry the bacteria that cause acute otitis media, which migrate from the nose and throat to the middle ear after an initial influenza virus infection paves the way.

The researchers based their therapy on the ability of viruses called phages to break out of bacteria they infect by using a special enzyme to destroy the cell walls. Phages infect bacteria in a way that is similar to how viruses infect animal cells. Once inside, the virus hijacks the cells biochemical machinery and forces it to make a number of copies of the virus. After the new crop of viruses is made, a viral enzyme breaks apart the infected bacterial cell wall and allows the new viruses to escape and infect additional cells......... Posted by: Sue      Read more         Source

March 22, 2007, 10:13 PM CT

Leukemic cells find safe haven

The cancer drug asparaginase fails to help cure some children with acute lymphoblastic leukemia (ALL) because molecules released by certain cells in the bone marrow counteract the effect of that drug, as per researchers at St. Jude Children's Research Hospital.

The scientists showed that mesenchymal cells in the bone marrow create a protective niche for leukemic cells by releasing large amounts of asparagine, an amino acid that nearby leukemic cells must have to survive but do not make efficiently. This extra supply of asparagine helps leukemic cells survive therapy with asparaginase, a drug that normally would deplete their supply of this vital nutrient, the scientists reported. Mesenchymal cells give rise to a variety of different tissues, such as osteoblasts (bone-building cells) and chondrocytes (cartilage-building cells), and form the nurturing environment where normal blood cells and leukemic cells grow.

"Leukemic cells that resist asparaginase and survive in this protective niche of the bone marrow might be the reason that leukemia recurs in some children who have been treated with this drug," said Dario Campana, M.D., Ph.D., a member of the St. Jude Oncology and Pathology departments.

Campana is senior author of the report that appears in the online pre-publication issue of "The Journal of Clinical Investigation."........ Posted by: Janet      Read more         Source

March 14, 2007, 10:23 PM CT

Obesity high among Baltimore's homeless

A small but telling study from the Johns Hopkins Childrens Center reveals an ominous trend: more than expected, obesity shadows Baltimores homeless children and their caregivers, putting them at high risk for heart disease, stroke and type 2 diabetes, among other conditions.

Not long ago, homeless people were undernourished. Our study shows the pendulum has swung the other way: Obesity might be the new form of malnutrition among the homeless, says lead author Kathleen Schwarz, M.D., a gastroenterologist at the Childrens Center. More disturbing, it appears that being both poor and homeless may increase ones obesity risk.

The study, reported in the recent issue of the online journal Medscape General Medicine, looked at 60 children, ages 2 to 18, and 31 caregivers recruited from eight homeless shelters in Baltimore. Nearly half of the children (25 out of 60) were either overweight or at risk for becoming overweight. Children with weight in the 85th to 95th percentile for their age are considered at risk, while those with weight above the 95th percentile are classified as overweight. The U.S. Centers for Disease Control does not use the term obese for children. Compared with children nationally, Baltimores homeless poor had a higher percentage of at-risk or overweight children, pointing to homelessness as an added risk......... Posted by: JoAnn      Read more         Source

March 13, 2007, 9:43 PM CT

Sleep Disorders Can Impair Children's IQs

Three decades ago, medical researchers began sounding the alarm about how lead exposure causes IQ deficits in children. Today, scientists at the University of Virginia Health System say children with sleep disorders can face similar risks of intellectual impairment.

UVa scientists have been studying sleep disturbances in children with enlarged tonsils and adenoids for the past seven years. In a recent study, they discovered that youngsters who snore nightly scored significantly lower on vocabulary tests than those who snore less often.

"Vocabulary scores are known to be the best single predictor of a child's IQ and the strongest predictor of academic success," explains Dr. Paul M. Suratt, a pulmonologist who directs the UVa Sleep Laboratory.

As per Dr. Suratt, the vocabulary differences linked to nightly snoring are equivalent to the IQ dissimilarities attributed to lead exposure. "Studies show that, even at nontoxic levels, lead exposure can reduce a child's IQ by more than seven points," he notes.

Sleep disorders can be intellectually and behaviorally detrimental to children because they interrupt the deep sleep patterns needed for healthy development. At night, children with sleep disorders can be observed snoring, snorting, gasping, tossing and turning. During the day, these children can be irritable, hyperactive and unable to concentrate......... Posted by: JoAnn      Read more         Source

March 11, 2007, 8:35 PM CT

Hormone Activity Explains Adolescent Mood Swings

The "raging hormones" of puberty are known to produce mood swings and stress for most teenagers, making it difficult to cope with this period of life. Until now, the specific causes of pubertal anxiety have not been identified, making it harder to understand and treat adolescent angst.

In the current edition of the journal Nature Neuroscience, scientists led by Sheryl S. Smith, PhD, professor of physiology and pharmacology at SUNY Downstate Medical Center, report findings demonstrating that a hormone normally released in response to stress, THP, actually reverses its effect at puberty, when it increases anxiety.

This hormone normally acts like a tranquilizer, acting at sites in the brain that "calm" brain activity. In the adult, this stress hormone helps the individual adapt to stress, with a calming effect produced half an hour after the event.

Specifically, the GABA-A receptor is the target for steroids, such as THP (or allopregnanolone), which reduce anxiety. GABA-A receptors calm activity in the brain. As such, they are the targets for most sedative, tranquilizing drugs.

One sub-type, GABA-A receptors containing the delta subunit, such as alpha4-beta2-delta, has the highest sensitivity to steroids. In order to study its role in puberty, the scientists used a mouse model that reliably predicts the human condition. In this rodent model, the alpha4-beta2-delta receptor normally has very low expression, but increases dramatically at the onset of puberty in the part of the brain that regulates emotion. Paradoxically, THP reduced the inhibition produced by these alpha4-beta2-delta GABA-A receptors, increasing brain activity to produce a state of increased anxiety. Stress also increased anxiety at puberty, due to the paradoxical effects of this hormone that is released by stress......... Posted by: JoAnn      Read more         Source