Wednesday, March 28, 2007

Novel Antimicrobial Peptide Discovered

he University of British Columbia is reporting the discovery of a new antimicrobial peptide by its researchers, in collaboration with Inimex Pharmaceuticals, a spin-off university company:

"Antibiotics are now under threat because of the explosion in antibiotic-resistant bacteria. A third of all deaths on this planet are the result of infection so there is an urgent need to create new therapies," says Robert Hancock, principal investigator and Canada Research Chair in Pathogenomics and Antimicrobials. "The beauty of this peptide is that it acts on the host to trigger a protective response and doesn't act on bacteria directly. That means it's unlikely bacteria will become resistant to it."

The team found that a peptide, or chain of amino acids, they have dubbed innate defense regulator peptide (IDR-1), can increase innate immunity without triggering harmful inflammation, and offer protection both before and after infection is present.

The discovery, in animal models, will be published March 25 in the journal Nature Biotechnology.

Researchers tested the peptide's effectiveness against Staphylococcus aureus including MRSA; a superbug called vancomycin-resistant Enterococcus (VRE); and Salmonella. In Staph and VRE infections, although bacteria were not completely eradicated, IDR-1 significantly reduced bacteria counts and mortality, when given either 24-48 hours before or four hours after infection began. In Salmonella, the peptide offered significant protection when administered prior to infection setting in.

Data showed that IDR-1 activates several signaling pathways to stimulate infection-clearing chemokines -- a chemical mediator that mobilizes immune response.

In addition, the peptide did not produce harmful inflammation and toxicity often seen when the immune system is stimulated and, in fact, actually reduced the potentially harmful septic response. Sepsis, a consequence of a ravaging inflammatory response associated with infection, kills as many as 200,000 annually.

Thursday, March 22, 2007

Trends in Tuberculosis Incidence: MMWR

In 2006, a total of 13,767 tuberculosis (TB) cases (4.6 per 100,000 population) were reported in the United States, representing a 3.2% decline from the 2005 rate. This report summarizes provisional 2006 TB incidence data from the National TB Surveillance System and describes trends since 1993. The TB rate in 2006 was the lowest recorded since national reporting began in 1953, but the rate of decline has slowed since 2000. The average annual percentage decline in the TB incidence rate decreased from 7.3% per year during 1993--2000 (95% confidence interval [CI] = 6.9%--7.8%) to 3.8% during 2000--2006 (CI = 3.1%--4.5%). Foreign-born persons and racial/ethnic minority populations continue to be affected disproportionately by TB in the United States. In 2006, the TB rate among foreign-born persons in the United States was 9.5 times that of U.S.-born persons.* The TB rates among blacks, Asians, and Hispanics† were 8.4, 21.2, and 7.6 times higher than rates among whites, respectively. The slowing of the decline in the overall national TB rate and the inability to effectively address persistent disparities in TB rates between U.S.-born and foreign-born persons and between whites and racial/ethnic minority populations threaten progress toward the goal of eliminating TB in the United States. In 1989, CDC and the Advisory Committee for the Elimination of Tuberculosis issued a strategic plan for the elimination of TB, setting an interim target case rate of 3.5 per 100,000 population by 2000 and ultimately the elimination of TB (i.e., <1 case per 1 million population) in the United States by 2010 (1).

TB is a nationally notifiable disease. Health departments in the 50 states and District of Columbia (DC) electronically report to CDC any TB cases that meet the CDC and Council of State and Territorial Epidemiologists case definition.§ Reports include the patient's race, ethnicity (i.e., Hispanic or non-Hispanic), treatment information, and drug-susceptibility test results if available. For this analysis, CDC calculated national and state TB rates (2) and rates for foreign-born and U.S.-born persons (3) and racial/ethnic populations (4) by using current U.S. census population estimates for the years 1993 through 2006.

In 2006, TB incidence rates in the 51 reporting areas ranged from 0.8 (Wyoming) to 12.6 (DC) cases per 100,000 population (median: 3.4 cases). Thirty states had lower rates in 2006 than 2005; 20 states and DC had higher rates (Table 1). In 2006, for the second consecutive year and the second time since national reporting began, approximately half of states (26 of 50) had TB rates of <3.5 per 100,000 (Figure 1); however, 11 of those 26 states had higher rates of TB in 2006 than in 2005. Seven states (California, Florida, Georgia, Illinois, New Jersey, New York, and Texas) reported more than 500 cases each for 2006; combined, these seven states accounted for 60% (8,259) of all TB cases.

Among U.S.-born persons, the number and rate of TB cases continued to decline in 2006. The U.S.-born TB rate was 2.3 per 100,000 population (5,924 or 43.3% of all cases with known origin of birth), representing a 7.0% decline in rate since 2005 and a 68.6% decline since 1993 (Figure 2).

Among foreign-born persons, the number of TB cases increased in 2006, but the rate decreased. The foreign-born TB rate in 2006 was 21.9 per 100,000 population, representing a 0.5% decline in rate since 2006 and a 35.8% decline since 1993. As the rate of decline in TB cases among foreign-born persons lagged behind the decline in TB cases among U.S.-born persons, the foreign-born to U.S.-born rate ratio increased 7.0%, from 8.9 in 2005 to 9.5 in 2006. In 2006, approximately half (55.6%) of TB cases among foreign-born persons were reported in persons from five countries: Mexico (1,912), the Philippines (856), Vietnam (630), India (540), and China (376).

In 2006, for the third consecutive year, more TB cases were reported among Hispanics than any other racial/ethnic population. Among persons with TB whose country of birth was known, 95.6% (3,126 of 3,269) of Asians, 74.7% (3,024 of 4,050) of Hispanics, 29.9% (1,110 of 3,712) of blacks, and 17.8% (427 of 2,404) of whites were foreign born. From 2005 to 2006, TB rates declined for all racial/ethnic minorities except American Indians/Alaska Natives and Native Hawaiians or Other Pacific Islanders¶ (Table 2).

Human immunodeficiency virus (HIV) contributes to the TB pandemic because immune suppression increases the likelihood of rapid progression from TB infection to TB disease. From 2005 to 2006, among TB cases with HIV status reported,** the percentage of TB cases with HIV infection decreased 4.4% (from 13.0% to 12.4%), but the percentage of TB cases with unknown HIV status increased 10.3% (from 28.7% to 31.7%).†† The decline in the percentage of TB cases with HIV infection might reflect incomplete reporting of HIV test results attributed to a lack of HIV testing or HIV reporting.

A total of 124 cases of multidrug-resistant TB (MDR TB)§§ were reported in 2005, the most recent year for which complete drug-susceptibility data are available.¶¶ The proportion of MDR-TB cases remained constant at 1.2% from 2004 (129 of 10,846 TB cases) to 2005 (124 of 10,662). In 2005, MDR TB continued to disproportionately affect foreign-born persons, who accounted for 101 (81.5%) of 124 MDR-TB cases.

The recommended length of drug therapy for most types of TB is 6--9 months. In 2003, the latest year for which treatment data are complete, 82.7% of patients for whom <1 year of treatment was indicated completed therapy within 1 year, below the Healthy People 2010 target of 90% (objective 14-12).

Tuesday, March 13, 2007

Time Travel

Well, I actually can't believe that researchers have spent time and money researching time travel. And, after all this time, the researchers say that time travel can't be done.
As if I needed a scientist to tell me that time travel can't be done.
This just iterates the old saying or rather definition of a doctor
A doctor is someone who know more and more about less and less until he knows everything about nothing


You Can't Travel Back in Time, Scientists Say

The urge to hug a departed loved one again or prevent atrocities are among the compelling reasons that keep the notion of time travel alive in the minds of many.

While the idea makes for great fiction, some scientists now say traveling to the past is impossible.

There are a handful of scenarios that theorists have suggested for how one might travel to the past, said Brian Greene, author of the bestseller, “The Elegant Universe” and a physicist at Columbia University.“And almost all of them, if you look at them closely, brush up right at the edge of physics as we understand it. Most of us think that almost all of them can be ruled out.”

The fourth dimension

In physics, time is described as a dimension much like length, width, and height. When you travel from your house to the grocery store, you’re traveling through a direction in space, making headway in all the spatial dimensions—length, width and height. But you’re also traveling forward in time, the fourth dimension.

“Space and time are tangled together in a sort of a four-dimensional fabric called space-time,” said Charles Liu, an astrophysicist with the City University of New York, College of Staten Island and co-author of the book “One Universe: At Home In The Cosmos.”

Space-time, Liu explains, can be thought of as a piece of spandex with four dimensions. “When something that has mass—you and I, an object, a planet, or any star—sits in that piece of four-dimensional spandex, it causes it to create a dimple,” he said. “That dimple is a manifestation of space-time bending to accommodate this mass.”

The bending of space-time causes objects to move on a curved path and that curvature of space is what we know as gravity.

Mathematically one can go backwards or forwards in the three spatial dimensions. But time doesn’t share this multi-directional freedom.

“In this four-dimensional space-time, you’re only able to move forward in time,” Liu told LiveScience.

Tunneling to the past

A handful of proposals exist for time travel. The most developed of these approaches involves a wormhole—a hypothetical tunnel connecting two regions of space-time. The regions bridged could be two completely different universes or two parts of one universe. Matter can travel through either mouth of the wormhole to reach a destination on the other side.

“Wormholes are the future, wormholes are the past,” said Michio Kaku, author of “Hyperspace” and “Parallel Worlds” and a physicist at the City University of New York. “But we have to be very careful. The gasoline necessary to energize a time machine is far beyond anything that we can assemble with today’s technology.”

To punch a hole into the fabric of space-time, Kaku explained, would require the energy of a star or negative energy, an exotic entity with an energy of less than nothing.

Greene, an expert on string theory—which views matter in a minimum of 10 dimensions and tries to bridge the gap between particle physics and nature's fundamental forces, questioned this scenario.

“Many people who study the subject doubt that that approach has any chance of working,” Greene said in an interview . “But the basic idea if you’re very, very optimistic is that if you fiddle with the wormhole openings, you can make it not only a shortcut from a point in space to another point in space, but a shortcut from one moment in time to another moment in time.”

* Video: How to Time Travel!

Cosmic strings

Another popular theory for potential time travelers involves something called cosmic strings—narrow tubes of energy stretched across the entire length of the ever-expanding universe. These skinny regions, leftover from the early cosmos, are predicted to contain huge amounts of mass and therefore could warp the space-time around them.

Cosmic strings are either infinite or they’re in loops, with no ends, said J. Richard Gott, author of “Time Travel in Einstein's Universe” and an astrophysicist at Princeton University. “So they are either like spaghetti or SpaghettiO’s.”

The approach of two such strings parallel to each other, said Gott, will bend space-time so vigorously and in such a particular configuration that might make time travel possible, in theory.

“This is a project that a super civilization might attempt,” Gott told LiveScience. “It’s far beyond what we can do. We’re a civilization that’s not even controlling the energy resources of our planet.”

Impossible, for now

Mathematically, you can certainly say something is traveling to the past, Liu said. “But it is not possible for you and me to travel backward in time,” he said.

However, some scientists believe that traveling to the past is, in fact, theoretically possible, though impractical.

Maybe if there were a theory of everything, one could solve all of Einstein’s equations through a wormhole, and see whether time travel is really possible, Kaku said. “But that would require a technology far more advanced than anything we can muster," he said. "Don’t expect any young inventor to announce tomorrow in a press release that he or she has invented a time machine in their basement.”

For now, the only definitive part of travel in the fourth dimension is that we’re stepping further into the future with each passing moment. So for those hoping to see Earth a million years from now, scientists have good news.

“If you want to know what the Earth is like one million years from now, I’ll tell you how to do that,” said Greene, a consultant for “Déjà Vu,” a recent movie that dealt with time travel. “Build a spaceship. Go near the speed of light for a length of time—that I could calculate. Come back to Earth, and when you step out of your ship you will have aged perhaps one year while the Earth would have aged one million years. You would have traveled to Earth’s future.”

More about Time Travel