How Anthrax Kills: Toxins Damage Liver and Heart

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How Anthrax Kills: Toxins Damage Liver and Heart

By Jesse Emspak, Contributing writer   |   August 28, 2013 01:06pm ET
Anthrax spores
This image shows spores from Bacillus anthracis bacteria, magnified more than 30,000 times.
Credit: Janice Haney Carr, via CDC

A new study of anthrax reveals why the infection is deadly.

The findings also offer clues that could be used to better treat people who are infected, which could possibly improve survival rates, researchers said in their study published  Thursday (Aug. 29) in the journal Nature.

Doctors in developed nations rarely see anthrax cases, but if they do, it’s important to treat the disease correctly, and as soon as possible, said Stephen Leppla, of the Laboratory for Infectious Diseases at the National Institutes of Health.

“The problem with clinicians treating anthrax is that nobody has much experience doing it,” Leppla said. Understanding exactly how anthrax kills can help clinicians tailor better strategies.

Anthrax is caused by bacteria, and can infect people in one of three ways: people might inhale the spores, eat the spores, or take in spores via the skin. All three types of infection can be deadly, though the skin route of infection is much less so, according to the Centers for Disease Control and Prevention. Inhaled anthrax has a mortality rate of about 75 percent, while the gastrointestinal infection kills about 60 percent of infected people, even with treatment. Among those infected through their skin, anthrax mortality drops to 20 percent. [Tiny & Nasty: Images of Things That Make Us Sick]

In the developing world, people become infected though contact with livestock. In the U.S. and Europe, anthrax is now very rare — only one or two cases appear yearly on average in the U.S.

Deadly toxins

The bacteria themselves aren’t what sickens and kills: it’s the toxins the bacteria produce. A doctor can treat a patient with antibiotics and kill all the anthrax bacteria – antibiotics are very effective against the infection. But the toxins the bacteria made remain in the body, and continue damaging cells.

The two toxins produced by anthrax, called lethal toxin and edema toxin, damage many types of cells, but it was thought that their effects on endothelial cells, which line blood and lymph vessels, were what made anthrax so lethal.

In the new study, it was found that wasn’t the case; rather, much of the toxins’ action seems to be in the cells of the heart muscle and the liver.

To track down which cells anthrax targeted, the researchers looked at mice genetically altered so that a protein called CMG2, to which anthrax toxins bind, was absent from their endothelial cells. They compared these mice with another group that had CMG2.

Results showed that both sets of mice were similarly sensitive to anthrax, which meant that anthrax wasn’t killing the mice via damage to endothelial cells.

The researchers next tested mice that were missing the CMG2 protein from their heart cells. Those mice survived the doses of lethal toxin much better than their litter mates that had the protein, which pointed to anthrax’s effects on the heart muscle as the way that it kills.

Similarly, mice without CMG2 in their liver cells fared better when exposed to edema toxin than mice that expressed CMG2, showing that the edema toxin affects the liver.

Leppla noted that it is not clear whether the findings are also true of anthrax in people. Future experiments on primates would confirm the results, he said.

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What Is Garcinia Cambogia?

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What Is Garcinia Cambogia?

By Lauren Cox, Contributing writer   |   August 28, 2013 09:09am ET
Garcinia cambogia fruit

The fruit Garcinia cambogia was once just the less popular cousin of a trendy fruit, the mangosteen. But now, nutritional supplements containing Garcinia cambogia extract have become the rage, touted for their purported ability to curb appetite and stop weight gain.

The gambooge fruit, also known as the Malabar tamarind, grows across southwest India, Myanmar and Indonesia. It ripens to a red or yellowish fruit about the size of an orange, but resembling the shape of a pumpkin.

People have long used the dried gambooge rinds for chutneys or curries, and sometimes as an aid for stomach problems. But in the late 1960s, scientists identified a substance in the rind of the fruit called hydroxycitric acid, or HCA, which has some potentially attractive qualities.

“Some studies have shown that HCA stops an enzyme that turns sugar into fat,” said Catherine Ulbricht, senior pharmacist at Massachusetts General Hospital in Boston and co-founder of Natural Standard Research Collaboration, which reviews evidence on herbs and supplements.

A fruit extract that could interfere with the body’s production of fat? The appeal is obvious. However, good results in test tubes don’t always translate to an entire person.

Does Garcinia cambogia work?

Some studies say HCA works, and some say it doesn’t. Animal studies of HCA showed that mice taking the substance ate less, lost weight and produced less fat from sugar.

Human studies had more conflicting results. One weight loss trial showed no difference between people who took Garcinia cambogia and those who took a placebo pill. Other trials linked HCA to weight loss and healthy blood lipid levels (lipids are fats).

“Further, well-designed clinical trials are needed before any firm conclusions can be made,” Ulbricht said.

If a pharmaceutical company wanted to sell HCA as a drug, the company would have to find stronger evidence that the substance worked, coming from better-designed clinical trials. Without that data, HCA wouldn’t pass U.S. Food and Drug Administration approval, Ulbricht said. But the FDA doesn’t put chemicals sold as nutritional supplements under the same burden of proof as pharmaceuticals. In fact, supplement makers only have to make their products safe to eat and responsibly label them.

Despite the popularity of Garcinia cambogia, it is difficult to track how effective supplements containing it are.

“Preparation of products may vary from manufacturer to manufacturer, and from batch to batch within one manufacturer,” Ulbricht said. That makes it difficult to compare one brand to another or even to measure the effects of a single brand.

Is Garcinia cambogia safe?

People may safely eat the fruit, of course. And clinical trials have shown it’s safe to take Garcinia cambogia extract by mouth — at least for 12 weeks, the length of the studies.

But take caution. Garcinia cambogia has side effects – it may lower a person’s blood sugar, so it can interact with diabetes treatments. The fruit hasn’t been adequately studied in pregnant women or women who breastfeed. And Garcinia cambogia may be a problem for patients with Alzheimer’s or other forms of dementia, Ulbricht said.

In 2009, the FDA issued a safety warning after receiving more than 20 reports of severe reactions, including liver damage, in people taking the supplement Hydroxycut. At the time, Hydroxycut contained Garcinia cambogia extract and other compounds, including chromium polynicotinate and Gymnema sylvestre extract.

Ulbricht said it’s unclear if the Garcinia cambogia extract caused the liver damage.

The bottom line is that people should tell their doctors before trying a new supplement, including Garcinia cambogia and HCA, she said.

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The Colorado Plateau: A Geological Wonderland

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The Colorado Plateau: A Geological Wonderland

Linda & Dr. Dick Buscher, OurAmazingPlanet Contributors   |   August 27, 2013 04:30pm ET

The Colorado Plateau

Credit: National Parks Service.
The Colorado Plateau is a geological wonderland that encompasses 130,000 square miles (337,000 square kilometers) centered around theFour Corners area of the American West and within the states of Colorado, New Mexico, Arizona and Utah. It ranges in elevation from slightly over 2,000 feet (600 meters) along the Colorado River in the Grand Canyon to over 12,000 feet (3,660 meters) in the Henry and La Sal Mountains of southeastern Utah. More than 90 percent of the plateau lands are drained by the Colorado River and its major tributaries, the Little Colorado, the San Juan and the Green rivers.

The landscape

Credit: Linda & Dr. Dick Buscher
This land is characterized by high mountains, rugged, eroded plateaus, river gorges, volcanic peaks, sandstone arches, spires and hoodoosand includes the splendor of the Grand Canyon. It is the most untamed landscape of the lower 48 states. It is also home to the largest cluster of national parks (10) and national monuments (17) found anywhere in the world. Ten Native American tribes claim the Colorado Plateau as their homeland and share the arid region with a multitude of unique and scarce high desert plants and animals.

An ancient area

Credit: Linda & Dr. Dick Buscher
The Colorado Plateau is extremely old — at least 500 million years and possibly older. It is a well-defined, thick mass of continental crust that has remained intact and avoided the common rock reformation (folding and faulting) that affects much of the rest of the planet. While the Western lands surrounding it were being broken and bent, stretched and uplifted, the Colorado Plateau amazingly remained unbroken.

Transition zone

Credit: Linda & Dr. Dick Buscher
The western boundary of the Colorado Plateau is marked by a large transition zone of common plateau geology and common Basin and Range Province. The northern boundary ends at the Uinta Mountains of Utah and the Rocky Mountains of Colorado. The Rio Grande Rift Valley of New Mexico, shown above in the Rio Grande Gorge, defines the eastern boundary and the Mogollon Rim of central and eastern Arizona marks the southern boundary. At the margins of the Colorado Plateau, major ancient volcanic fields are found.

Six contrasting sections

Credit: Linda & Dr. Dick Buscher
The Colorado Plateau has been divided into six, contrasting sections. The Datil section is located in eastern Arizona and western New Mexico and is mainly volcanic in origin. Here is found the Springerville Volcanic Field, an area of 1,160 square miles (3,000 square kilometers) with more than 400 dormant volcanic vents. The Springerville Volcanic Field, shown above, is third largest volcanic field in the continental United States.

The Grand Canyon

Credit: Linda & Dr. Dick Buscher
The Grand Canyon section is located in the southwestern and western edge of the Colorado Plateau. It is home, as its name suggests, to the magnificent Grand Canyon. Along the southeastern part of this section is found the San Francisco Volcanic Field, the largest volcanic field in the continental United States, with more than 600 ancient volcanic vents. The last volcanic eruption in this field occurred in 1064-1065 at Sunset Crater, near Flagstaff, Ariz.

The High Plateau

Credit: Jessi Brunson/US Fish & Wildlife Service
The High Plateau section is located along the western and northwestern part of the Colorado Plateau. It is characterized by large plateaus separated by local faults. This section is home to the incredible geological formations of Zion and Bryce Canyon National Parks. The picture above shows a hiking trail passing through Bryce Canyon.

The Uinta Basin

Credit: Linda & Dr. Dick Buscher
The Uinta Basin is found in the northernmost part of the Colorado Plateau and is the lowest part of the great plateau. Many of the smaller tributaries of the Green River have their origin here in the Uinta Mountains. The great Spanish explorer, Father Silvestre Velez de Escalante, first visited this area in September 1776. The photo above is of the rare and endangered Barneby Ridge Cress (Lepidium barnebyanum) found only in the Uinta Basin.

The Canyonlands

Credit: Linda & Dr. Dick Buscher
The Canyonlands section is located in the northeastern part of the Colorado Plateau and is home to deeply cut canyons in a high desert environment. The landscape has been shaped and carved by the drainage systems of both the Green and Colorado Rivers. This is a land of spectacular vistas and home to both Canyonlands and Arches National Park. The photo above is of the formation known as Double Arch.

The Navajo

Credit: Linda & Dr. Dick Buscher
The Navajo section of the Colorado Plateau is home to the Four Corners area of the American Southwest. It is the central area of the Colorado Plateau, with landscapes of high plateaus separated by arid, high desert valleys. Many national monuments like Canyon de Chelley and Navajo Tribal Parks like Lake Powell and Monument Valley, shown above, are located in this dramatic section of the Colorado Plateau.

Deep canyons

Credit: Linda & Dr. Dick Buscher
Because of the eroding effect of the rivers that crisscross the Colorado Plateau, the many deep canyons found here are like an open textbook of geological time. Precambrian metamorphosed gneiss and schist lie exposed at the bottom of the Grand Canyon and are thought to be over 1,600 million years. The brilliant colors of the thick layers of sandstone and limestone sedimentary rocks resulted from the 380 million to 145 million-year-old ancient seas of the Permian.

Dry air

Credit: Linda & Dr. Dick Buscher
The arid climate of the Colorado Plateau is the result of a rain shadow caused by the Sierra Nevada Mountains located to the west of the plateau. Average annual precipitation (including rain and snow) ranges from 6 to 16 inches (15 to 40 centimeters). In the higher elevations more precipitation occurs and results in forests of pine, spruce and fir.

Diverse ecology

Credit: Linda & Dr. Dick Buscher
The Colorado Plateau is a region of great ecological diversity. From thick riparian river banks lined with forests of cottonwood trees to miles and miles of dry desert basins covered with saltbush and greasewood; from grass covered mountain meadows to ponderosa pine covered mountain peaks — all varieties of nature’s botanical species are represented in this rugged, untamed wilderness. During late spring and early summer wildflowers abound all across the plateau.

Diverse wildlife

Credit: Linda & Dr. Dick Buscher
The wildlife of the Colorado Plateau is as diverse as the landforms, vegetation and the climate. Collared lizards, elk, rattlesnakes, cougars, bobcats, jackrabbits, mule deer and more all roam across the land seeking to survive in this harsh environment. This collared lizard, shown here, is enjoying the springtime sun at Arches National Park.

Home to variety

Credit: Linda Buscher
A vast variety of birds fill the sky over the Colorado Plateau. Stellar jays, wild turkeys, various species of hawks and falcons are found here. Many migratory songbirds move across the Colorado Plateau each spring and fall. The Colorado Plateau is once again home to California condors that now again soar above the deep chasms of the Grand Canyon thanks to the successful efforts of a condor reintroduction program near the Vermillion Cliffs of northern Arizona.

Unique in all the world

Credit: Linda & Dr. Dick Buscher
American author and environmentalist Edward Abbey, when asked about the uniqueness of the Colorado Plateau, stated that “there is no other region on Earth much like it, or even remotely like it … this is a landscape that has to be seen to be believed, and even then, when confronted directly by the senses, it strains credulity.”