Monday, May 10, 2010

HISTORIC MEDICAL CONFERENCE FINDS BOLIVAR MAY HAVE BEEN POISONED

0 comentarios
Could one of South America's greatest military figures have died from a deadly poison, rather than the tuberculosis assumed at the time of his death in 1830?

The mysterious illness and death of Simon Bolivar — known as "El Libertador" or "The Liberator" — is the medical mystery in question at this year's Historical Clinicopathological Conference (CPC), sponsored by the University of Maryland School of Medicine and the Veterans Affairs (VA) Maryland Health Care System in Baltimore. This conference is devoted to the modern medical diagnosis of disorders that affected prominent historical figures.

Simon Bolivar, born in 1783 in Caracas, Venezuela, is one of the most influential generals in the history of South America. Bolivar, who died of a mysterious illness at age 47, led the long struggle that freed South America from three centuries of Spanish rule. Bolivar established the nation of Bolivia — previously part of Peru — in 1825, and the new country was named in his honor. Now, French Guyana is the only South American nation that remains a colony.

The Embassy of the Bolivarian Republic of Venezuela in the United States will send two representatives to the conference: Counselor Regzeida Gonzalez and Raquel del Rocio Gasperi, director of the Technical and Scientific Unit at the Office of the Public Prosecutor of Venezuela, who was part of the country's Presidential Commission to investigate the death Bolivar.

During the conference, John Dove, MBBS, a Bolivar scholar and orthopedic surgeon from Scotland, will describe Bolivar's accomplishments and the somewhat controversial role he has played in South American history.

"Bolivar ended 300 years of colonization in South America," says Dr. Dove. "He was a liberator and a brilliant hands-on commander. The figures speak for themselves. Bolivar covered more than 80,000 miles and spread the idea of freedom over an area greater than one and a half times the diameter of the earth."

Dove's fellow presenter at this year's CPC is Paul G. Auwaerter, M.D., M.B.A., associate professor and clinical director in the Division of Infectious Diseases in the Department of Medicine at the Johns Hopkins University School of Medicine. Dr. Auwaerter has taken on the challenge of unraveling the mystery of Bolivar's death.

When Bolivar died on December 17, 1830, it was believed he was succumbed to consumption or tuberculosis, a common condition of the day. He had suffered a long illness with a variety of symptoms — frequent bouts of loss of consciousness, skin darkening, extreme weight loss, coughing, exhaustion and persistent headaches.

Dr. Auwaerter, in his careful review of Bolivar's case, has concluded the general's killer was likely not tuberculosis. Rather, Dr. Auwaerter sees evidence of a more sinister cause of death — chronic arsenic poisoning that led to a serious respiratory illness. Considering the many attempts on Bolivar's life throughout his career as a revolutionary, Dr. Auwaerter says he has considered the possibility that the death was an assassination. But most of the signs and symptoms point to slow, chronic poisoning, the kind that might result from drinking contaminated water. Such environmental contact with arsenic would have been entirely possible, Dr. Auwaerter says.

"Bolivar spent a lot of time in Peru, and there have been Colombian mummies found there that have tested positive for high levels of arsenic," he explains. "That indicates the possibility that the water in Peru may have had unusually high levels of the naturally occurring poison."

But that's not all, he adds: "Bolivar was known to ingest arsenic as a remedy for some of his ongoing illnesses — recurring headaches, wasting, hemorrhoids and his chronic episodes of unconsciousness. Arsenic was actually a common medical remedy of the time. In fact, it has recently been discovered that a contemporary leader of Bolivar's, George III, had super-high levels of arsenic in his body tissue and air. It seems he had been treating himself with it."

While the possibility of an assassination certainly adds intrigue to Bolivar's story, "It's unlikely this was acute poisoning," Dr. Auwaerter explains. "What I'm finding is more consistent with chronic poisoning because of symptoms such as his skin darkening, his headaches, his extreme weight loss. His whole body is really falling apart at the end. He lived for quite some time like this. I believe it's likely he would have succumbed to tuberculosis much earlier than he did. The idea of gradual arsenic poisoning is a good explanation to link all these symptoms together."

Dr. Auwaerter began his search by considering the nature of the illness that ultimately led to Bolivar's demise. For the last two weeks of his life, he was emaciated and weak and coughed constantly, producing large amounts of green sputum. The autopsy found signs of green fluid in the lungs and in the heart. Bolivar's doctors concluded he died of tuberculosis because of the respiratory aspect of this final illness.

"This was an era where there was really no ability to confirm that someone had died of tuberculosis," Dr. Auwaerter says. "That green fluid in the lungs and heart is very suggestive of a bacterial infection called bronchiecstasis, which was very common at the time. The green pericardial fluid is very unlikely to represent tuberculosis."

Bolivar also appeared to have had a tumor in his lungs that caused him to be severely hoarse, with a voice so quiet he could hardly be heard for the last six months of his life. Lung cancer could be another complication of chronic poisoning, Dr. Auwaerter adds.

"It's very hard to be definitive here," he explains. "I have to say that tuberculosis is not an unreasonable explanation for his death. But, at the end of the day, there are a lot of features of this illness that argue against tuberculosis. If the body were ever to be exhumed, there would be a lot of things to look at. Arsenic testing on Bolivar's tissue and hair could answer some of our questions."

"Whereas Dr. Auwaerter makes a compelling case for chronic arsenic intoxication complicated by bronchiectasis and lung cancer, I have no doubt that the controversy regarding the ideology of the general's fatal illness will continue until his remains are re-examined using modern diagnostic techniques," Philip A. Mackowiak, M.D., M.B.A., professor and vice chair of the Department of Medicine of the University of Maryland School of Medicine and Chief of the Medical Care Clinical Center of the VA Maryland Health Care System. Dr. Mackowiak founded the annual CPC in 1995, and the program has since examined the lives and deaths of famous figures such as Edgar Allan Poe and Abraham Lincoln.

"Medicine is very much a field of detective work," says E. Albert Reece M.D., Ph.D., M.B.A., interim president of the University of Maryland, Baltimore, John Z. and Akiko K. Bowers Distinguished Professor and dean, University of Maryland School of Medicine. "Ordinarily, our world class faculty here at the School of Medicine are solving mysteries in the realm of human health in the laboratory and in the clinic. The CPC is a chance for our colleagues in medicine to apply our skills to history, and to revisit the state of our field centuries ago. It reminds us how far we've come, and how the groundbreaking discoveries we make every day will revolutionize medicine for future generations."

Dr. Auwaerter says he enjoyed the challenge of taking on the Bolivar mystery. "I've done a lot of background research to put these ideas together," he says. "I'm not a historian, so this is not usually my thing. But this is just the sort of puzzle I like thinking about."

University of Maryland Medical Center

LOTTERY GAME HELPS TO ASSESS BRAIN DAMAGE FOLLOWING STROKE

0 comentarios
Patients recovering from stroke sometimes behave as if completely unaware of one half of the world: colliding with obstacles on their left, eating food only from the right side of their plate, or failing to dress their left side. This puzzling phenomenon is termed "spatial neglect" and it affects roughly 45% of patients suffering from a stroke in the right side of the brain.

The condition can indicate a long road to recovery, but researchers have now developed a quick and simple lottery game, which can be used to assess the extent of these symptoms and potentially aid the design of rehabilitation programmes. The findings are reported in the May 2010 issue of Elsevier's Cortex (http://www.elsevier.com/locate/cortex).

Dr Tobias Loetscher (University of Melbourne) and colleagues studied a group of stroke patients, using tests based on a simple lottery game in which patients first chose six lottery numbers by marking them with a pencil on a real lottery ticket. Predictably, the patients with spatial neglect tended to pick numbers located on the right-hand side of the ticket, neglecting those on the left.

However, spatial neglect does not only affect a patient's interaction with the "real world"; it can also affect spatial imagination. In the second part of the test, patients were asked to spontaneously name six numbers without the aid of a lottery ticket. It is commonly believed that when we think of numbers we visualize them arranged along a mental number line with numbers increasing from left to right. The results of the study showed some patients picking only large numbers, indicating that they were unable to access the left side of mental images.

The information obtained from such simple bed-side tests could potentially be used to tailor effective rehabilitation procedures, which suit the individual patient. For example, patients who show signs of spatial neglect when marking numbers on the real lottery ticket, but not when picking numbers from their imagination, could be taught how to scan the missing part of their "real world", since they may be able to envisage it in their minds.

Elsevier B.V.

NANODOTS BREAKTHROUGH MAY LEAD TO A LIBRARY ON ONE CHIP

0 comentarios
A researcher at North Carolina State University has developed a computer chip that can store an unprecedented amount of data – enough to hold an entire library’s worth of information on a single chip. The new chip stems from a breakthrough in the use of nanodots, or nanoscale magnets, and represents a significant advance in computer-memory technology.

“We have created magnetic nanodots that store one bit of information on each nanodot, allowing us to store over one billion pages of information in a chip that is one square inch,” says Dr. Jay Narayan, the John C. Fan Distinguished Chair Professor of Materials Science and Engineering at NC State and author of the research.

The breakthrough is that these nanodots are made of single, defect-free crystals, creating magnetic sensors that are integrated directly into a silicon electronic chip. These nanodots, which can be made uniformly as small as six nanometers in diameter, are all precisely oriented in the same way – allowing programmers to reliably read and write data to the chips.

The chips themselves can be manufactured cost-effectively, but the next step is to develop magnetic packaging that will enable users to take advantage of the chips – using something, such as laser technology, that can effectively interact with the nanodots.

North Carolina State University

MELTING ICEBERGS CAUSING SEA LEVEL RISE

0 comentarios

Scientists have discovered that changes in the amount of ice floating in the polar oceans are causing sea levels to rise.

The research, published in Geophysical Research Letters, is the first assessment of how quickly floating ice is being lost today.

According to Archimedes' principle, any floating object displaces its own weight of fluid. For example, an ice cube in a glass of water does not cause the glass to overflow as it melts.

But because sea water is warmer and more salty than floating ice, changes in the amount of this ice are having an effect on global sea levels.

The loss of floating ice is equivalent to 1.5 million Titanic-sized icebergs each year. However, the study shows that spread across the global oceans, recent losses of floating ice amount to a sea level rise of just 49 micrometers per year – about a hair's breadth.

According to lead author Professor Andrew Shepherd, of the University of Leeds, it would be unwise to discount this signal. "Over recent decades there have been dramatic reductions in the quantity of Earth's floating ice, including collapses of Antarctic ice shelves and the retreat of Arctic sea ice," said Prof Shepherd.

"These changes have had major impacts on regional climate and, because oceans are expected to warm considerably over the course of the 21st century, the melting of floating ice should be considered in future assessments of sea level rise."

Professor Shepherd and his team used a combination of satellite observations and a computer model to make their assessment. They looked at changes in the area and thickness of sea ice and ice shelves, and found that the overall signal amounts to a 742 cubic kilometres per year reduction in the volume of floating.

Because of differences in the density and temperature of ice and sea water, the net effect is to increase sea level by 2.6% of this volume, equivalent to 49 micrometers per year spread across the global oceans.

The greatest losses were due to the rapid retreat of Arctic Sea ice and to the collapse and thinning of ice shelves at the Antarctic Peninsula and in the Amundsen Sea.

(Photo: U. Leeds)

University of Leeds

RARE 95-MILLION-YEAR-OLD FLYING REPTILE AETODACTYLUS HALLI IS NEW PTEROSAUR GENUS, SPECIES

0 comentarios

A 95 million-year-old fossilized jaw discovered in Texas has been identified as a new genus and species of flying reptile, Aetodactylus halli.

Aetodactylus halli is a pterosaur, a group of flying reptiles commonly referred to as pterodactyls.

The rare pterosaur — literally a winged lizard — is also one of the youngest members in the world of the pterosaur family Ornithocheiridae, according to paleontologist Timothy S. Myers, who identified and named Aetodactylus halli. The newly identified reptile is only the second ornithocheirid ever documented in North America, says Myers, a postdoctoral fellow in the Huffington Department of Earth Sciences at Southern Methodist University in Dallas.

Aetodactylus halli would have soared over what is now the Dallas-Fort Worth area during the Cretaceous Period when much of the Lone Star state was under water, covered by a vast ancient sea.

While rare in North America, toothed pterosaurs belonging to the Ornithocheiridae are a major component of Cretaceous pterosaur faunas elsewhere in the world, Myers says. The Texas specimen — a nearly complete mandible with most of its 54 teeth missing — is definitively younger than most other ornithocheirid specimens from Brazil, England and China, he says. It is five million years younger than the only other known North American ornithocheirid.

Myers describes the new species in the latest issue of the Journal of Vertebrate Paleontology. Go to http://www.smuresearch.com/ to see illustrations of Aetodactylus halli and the Cretaceous marine environment, an image of the fossilized jaw and links to more information.

Myers named the pterosaur Aetodactylus halli after Lance Hall, a member of the Dallas Paleontological Society who hunts fossils for a hobby. Hall found the specimen in 2006 in North Texas. It was embedded in a soft, powdery shale exposed by excavation of a hillside next to a highway. The site was near the city of Mansfield, southwest of Dallas. Hall donated the specimen to SMU.

Pterosaurs ruled the skies from the late Triassic, more than 200 million years ago, to the end of the Cretaceous, about 65 million years ago, when they went extinct. They represent the earliest vertebrates capable of flying.

The Aetodactylus halli jaw was discovered in the geologic unit known as the Eagle Ford Group, which comprises sediments deposited in a shallow sea, Myers says. Outcrop of the Eagle Ford Group extends northward from southwestern Texas into southern Oklahoma and southwestern Arkansas.

"I was scanning the exposure and noticed what at first I thought was a piece of oyster shell spanning across a small erosion valley," Hall recalls of the discovery. "Only about an inch or two was exposed. I almost passed it up thinking it was oyster, but realized it was more tan-colored like bone. I started uncovering it and realized it was the jaw to something — but I had no idea what. It was upside down and when I turned over the snout portion it was nothing but a long row of teeth sockets, which was very exciting."

SMU vertebrate paleontologist Louis L. Jacobs, a dinosaur expert internationally recognized for his fossil discoveries in Texas and Africa, and SMU paleontologist Michael J. Polcyn, recognized for his expertise on the extinct marine reptiles called mosasaurs, both told Hall it was a pterosaur and an important find.

The 38.4-centimeter Aetodactylus jaw originally contained 54 slender, pointed teeth, but only two remain in their sockets, Myers says. The lower teeth were evenly spaced and extended far back along the jaw, covering nearly three quarters of the length of the mandible. The upper and lower teeth interlaced when the jaws were closed.

In Aetodactylus, changes in tooth size along the jaw follow a similar pattern to those of other ornithocheirids. However, Aetodactylus differs from all other ornithocheirids in that its jaws were thin and delicate, with a maximum thickness not much greater than 1 centimeter, Myers says. But the specimen does compare favorably with Boreopterus, a related pterosaur from the Early Cretaceous of China, in terms of the number of teeth present in the lower jaw, he says.

Myers has estimated the wingspan around roughly 3 meters, or about 9 feet, indicating Aetodactylus would have been a "medium-sized" pterosaur, he says. While it's not known how Aetodactylus died, at the time of death the reptile was flying over the sea and fell into the water, perhaps while fishing, Jacobs says.

North American pterosaurs that date from the Cretaceous are all toothless, except for Aetodactylus and Coloborhynchus, Myers says. The thinness of the jaws, the upward angle of the back half of the mandible and the lack of a pronounced expansion of the jaw tips indicate that Aetodactylus is different from other ornithocheirids and represents a new genus and species of pterosaur.

"Discovery of another ornithocheirid species in Texas hints at a diversity of pterosaurs in the Cretaceous of North America that wasn't previously realized," Myers says. "Aetodactylus also represents one of the final occurrences of ornithocheirids prior to the Late Cretaceous transition to pterosaur faunas that were dominated by the edentulous, or toothless, species."

Much of Texas was once submerged under the Western Interior Seaway. The massive sea split North America from the Gulf of Mexico to the Arctic Ocean.

On shore, the terrain was flat and flowering plants were already dominating flora communities in this part of North America, according to paleobotanist Bonnie Jacobs, associate professor of Earth Sciences at SMU.

"There were still conifers and ferns as well, but mostly of the sort that had tiny needle leaves, like junipers," says Bonnie Jacobs. "Sycamores and their relatives would have been among the flowering plants."

The first ornithocheirid remains from North America, discovered in Fort Worth, were described by former SMU student Young-Nam Lee and donated by amateur collector Chris Wadleigh, says SMU's Louis Jacobs.

"The ancient sea that covered Dallas provided the right conditions to preserve marine reptiles and other denizens of the deep, as well as the delicate bones of flying reptiles that fell from their flight to the water below," says Louis Jacobs, a professor in SMU's Huffington Department of Earth Sciences. "The rocks and fossils here record a time not well represented elsewhere in North America. That's why two species of ornithocheirids have been found here but nowhere else, and that's why discoveries of other new fossils are sure to be made by Lance Hall and other fossil lovers."

(Photo: Karen Carr)

Southern Methodist University

EARTH MICROBES MAY CONTAMINATE THE SEARCH FOR LIFE ON MARS

0 comentarios

Bacteria common to spacecraft may be able to survive the harsh environs of Mars long enough to inadvertently contaminate Mars with terrestrial life according to research published in the April 2010 issue of the journal Applied and Environmental Microbiology.

The search for life on Mars remains a stated goal of NASA’s Mars Exploration Program and Astrobiology Institutes. To preserve the pristine environments, the bioloads on spacecraft headed to Mars are subject to sterilization designed to prevent the contamination of the Martian surface.

Despite sterilization efforts made to reduce the bioload on spacecraft, recent studies have shown that diverse microbial communities remain at the time of launch. The sterile nature of spacecraft assembly facilities ensures that only the most resilient species survive, including acinetobacter, bacillus, escherichia, staphylococcus and streptococcus.

Researchers from the University of Central Florida replicated Mars-like conditions by inducing desiccation, hypobaria, low temperatures, and UV irradiation. During the week-long study they found that Escherichia coli a potential spacecraft contaminant, may likely survive but not grow on the surface of Mars if it were shielded from UV irradiation by thin layers of dust or UV-protected niches in spacecraft.

“If long-term microbial survival is possible on Mars, then past and future explorations of Mars may provide the microbial inoculum for seeding Mars with terrestrial life,” say the researchers. “Thus, a diversity of microbial species should be studied to characterize their potential for long term survival on Mars.”

(Photo: NASA)

American Society for Microbiology

Followers

Archive

 

Selected Science News. Copyright 2008 All Rights Reserved Revolution Two Church theme by Brian Gardner Converted into Blogger Template by Bloganol dot com