A new national computer network linking public health laboratories is expected to help epidemiologists identify potentially serious outbreaks of foodborne infection and trace their source.
The system, dubbed "PulseNet," uses a technique called pulsed-field gel electrophoresis, which allows scientists to create a distinctive DNA fingerprint for the infectious agent causing the outbreak. Subtle differences in these molecular fingerprints make it possible to determine whether cases of illness caused by a pathogen such as Escherichia coli O157:H7 can be traced to the same contaminated food source.
Under the new networked computer system launched in late May, public health laboratories in 16 states can create molecular fingerprints of pathogens associated with foodborne illnesses in their regions and share that information with other laboratories in the network via the Internet. Public health laboratories in the remaining states will be linked with the system by 1999.
FoodNet, a forerunner of PulseNet that tracked outbreaks in a handful of states, identified the E coli O157:H7 strain responsible for an outbreak of illness last year caused by contaminated ground beef.
"PulseNet can help public health experts recognize that foodborne illnesses occurring at the same time but in widely dispersed locations are from the same strain, and may be from a common exposure," said Claire Broome, MD, acting director of the Centers for Disease Control and Prevention. "By matching bacterial subtype patterns, we can detect nationwide outbreaks quickly and better direct public health actions."
Initially, PulseNet participants will perform DNA fingerprinting on E coli O157:H7 isolates and report their findings to the CDC database. The CDC will later expand the network's capabilities by creating databases of molecular subtypes of other foodborne pathogens.
Physicians and patients interested in learning about clinical trials testing treatments for eye diseases may find answers in a new interactive, searchable database on clinical trials supported and conducted by the National Eye Institute (NEI) since 1970. The database contains detailed information about completed and ongoing clinical trials on such conditions as retinopathy of prematurity and age-related macular degeneration.
Those using the database can search for trials using a key word, eye disease, or geographic location. Each trial description includes information about the background and purpose of the study, patient eligibility criteria, patient recruitment, current status of the trial (currently recruiting, ongoing but no longer recruiting, or completed), and contact information for each clinical center and/or NEI representative affiliated with the trial.
Also included are summaries of completed trials, along with their results and a bibliography; recommendations for clinical practice, based on the results of trials supported by the NEI; and descriptions of prevention-oriented natural history studies, some of which have clinical trial components. The site also includes information for physicians on how to refer a patient to a trial and for patients on how to participate in a trial.
The database is available at the NEI's Web site (http://www.nei.nih.gov).
Breaking up is hard to do—especially for smokers who seek to sever their relationship with nicotine. Now, a new study funded by the National Institute on Drug Abuse (NIDA) may provide some clues as to why many people find quitting the smoking habit so difficult and may suggest better ways of treating nicotine withdrawal (Nature. 1998;393:76-79).
Abrupt withdrawal from chronic nicotine exposure induces the same kind of withdrawal reaction in the brain's pleasure circuits seen with cocaine, opiates, amphetamines, and alcohol, according to animal studies conducted by researchers from the Scripps Research Institute.
Rats were given steady doses of nicotine to produce blood levels equivalent to those of a person smoking 1 ½ packs of cigarettes a day for 1 week. To measure the sensitivity of the rats' brains to pleasurable stimulation, the researchers allowed the rats to self-administer pulses of electricity in the lateral hypothalamus, part of the brain's reward circuitry.
When the animals were receiving steady doses of nicotine, sensitivity to brain reward remained stable, as measured by the amount of self-stimulation of electrical pulses. The investigators found that when the nicotine was withdrawn, the animals required 40% more electrical current to activate the brain's reward circuitry, indicating a significant decrease in sensitivity of the brain to pleasurable stimulation during nicotine withdrawal.
The results are comparable to the altered brain reward sensitivity seen in withdrawal from other addictive drugs.
"Understanding these decreases in the brain's sensitivity to pleasurable stimulation that occur during nicotine abstinence helps explain why it is so hard for people to stop smoking," said Alan I. Leshner, MD, director of NIDA. "This understanding may also help in the development of better treatments to address the withdrawal symptoms—depression, anxiety, irritability, and craving—that interfere with people's attempts to quit smoking.
The similarity of nicotine and other drugs of abuse in terms of withdrawal suggests that common characteristics, including a decrease in sensitivity to pleasure, underlie withdrawal from all addictive substances, he added.
Proponents of telehealth—using technology to support long-distance health care services and education—say the practice holds the promise of improving delivery of medical care to medically underserved or isolated Americans. To that end, the Health Resources and Services Administration (HRSA) announced the establishment of a new Office for the Advancement of Telehealth to encourage development of telehealth programs.
"This new office allows HRSA to facilitate and capture opportunities presented by emerging technology," said HRSA administrator Claude Earl Fox, MD, MPH. "We intend to build on and advance the use of telecommunications to increase and improve technical assistance to our grantees, to train health care providers, to encourage linkages for knowledge exchange, and to capitalize on and replicate lessons learned in providing quality health care to underserved individuals, families, and communities."
The new office's responsibilities will include telehealth policy and program development, telemedicine demonstrations in medically underserved and remote areas, providing technical assistance to local and state health officials, and producing public health education tools.
Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature
Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal
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