New study suggests Columbus brought syphilis to Europe from New World
Did Columbus and his men introduce the syphilis pathogen into Renaissance Europe after contracting it during their voyage to the New World? Or does syphilis have a much longer history in the Old World? The most comprehensive comparative genetic analysis conducted on the family of bacteria (the treponemes) that cause syphilis and related diseases such as yaws, published Tuesday, January 15 in PLoS Neglected Tropical Diseases, supports the so-called "Columbian theory” of syphilis’s origins.
Kristin Harper (Emory University, Atlanta, USA) approached this centuries-old debate by using phylogenetics — the study of the evolutionary relatedness between organisms — to study 26 geographically disparate strains of treponemes. The venereal syphilis-causing strains originated most recently, and their closest relatives were strains collected in South America that cause the treponemal disease yaws.
"That supports the hypothesis that syphilis - or some progenitor - came from the New World,” Harper says.
While it is generally agreed that the first recorded epidemic of syphilis occurred in Europe in 1495, controversy has raged ever since over the origin of the pathogen. Most of the evidence in recent years has come from bones of past civilizations in both New World and Old World sites, since chronic syphilis causes skeletal lesions. In many cases, however, skeletal analysis is inconclusive, due to problems with pinpointing the age of the bones and the lack of supporting epidemiological evidence.
Further complicating the research is the fact that the family of Treponema bacteria causes different diseases that share some symptoms but have different modes of transmission. Syphilis is sexually transmitted, but yaws and endemic syphilis are tropical diseases that are transmitted through skin-to-skin or oral contact. One hypothesis is that a subspecies of Treponema from the warm, moist climate of the tropical New World mutated into the venereal, syphilis-causing subspecies to survive in the cooler and relatively more hygienic European environment.
The phylogenetic analysis indicated that yaws is an ancient infection in humans while venereal syphilis arose relatively recently. The study results are especially significant due to the large number of different strains analyzed, including two never-before-sequenced strains of yaws from isolated inhabitants of Guyana's interior. At Harper's request, the Guyana samples were collected during a medical mission by Ve’ahavta, the Canadian Jewish Humanitarian and Relief Committee.
"Syphilis was a major killer in Europe during the Renaissance,” says co-author George Armelagos, a skeletal biologist whose research put him at the forefront of the syphilis debate 30 years ago. "Understanding its evolution is important not just for biology, but for understanding social and political history. It could be argued that syphilis is one of the important early examples of globalization and disease, and globalization remains an important factor in emerging diseases.”
CITATION: Harper KN, Ocampo PS, Steiner BM, George RW, Silverman MS, et al. (2008) On the Origin of the Treponematoses: A Phylogenetic Approach. PLoS Negl Trop Dis 2(1): e148. doi:10.1371/journal.pntd.0000148
Internal Medicine organization issues guidelines to improve care of 3 symptoms at end of life
PHILADELPHIA, Jan. 15, 2008 -- The American College of Physicians (ACP) has issued new guidelines to improve palliative care at the end of life (EOL).
The guidelines say that clinicians should regularly assess people with serious illness at the end of life for symptoms of pain, shortness of breath, and depression; that they should use proven therapies to treat these conditions; and should ensure that advance care planning occurs for all patients with serious illness.
"Many Americans will face a serious illness at the end of life and their families will be involved in their care,” said Amir Qaseem, MD, PhD, MHA, Senior Medical Associate in the Clinical Programs and Quality of Care Department of the Medical Education and Publishing Division at ACP. "We wanted to pull together best available evidence on improving care that relieves or soothes symptoms at the end of life. Evidence review showed that the three most common symptoms were pain, difficult breathing and depression, so our guidelines address these.”
Elaborating on the recommendations to use therapies of proven effectiveness to manage pain, shortness of breath, and depression, the guidelines say that clinicians should regularly assess patients with serious illness at the end of life.
For patients with cancer, pain has been proven to be controlled with anti-inflammatory drugs, narcotic drugs and bisphosphonates.
In patients at the end of life with difficult breathing, unrelieved dyspnea can be relieved by narcotic drugs and oxygen for short-term relief of hypoxemia.
Patients with depression can be treated with antidepressants and psychosocial intervention.
ACP, through its Clinical Efficacy Assessment Subcommittee, has been developing guidelines since 1981. ACP guidelines have relied on evidence or clinical documentation rather than consensus or expert opinion.
In the case of the EOL guidelines, the reviewing committee found that high-quality evidence on end-of-life care is limited, and most of the evidence comes from literature on patients with cancer. Therefore the new evidence-based guidelines could not address many other important aspects of EOL care, such as symptoms specific to heart disease, lung disease, or dementia, or therapies such as nutritional support, complementary and alternative therapies, and spiritual care.
The EOL guidelines were passed by the ACP Board of Regents on July 14, 2007.
"End of life care has been identified by the Institute of Medicine as one of the priority areas to improve quality of health care. We hope that these guidelines would benefit physicians taking care of patients with seriously disabling or symptomatic chronic conditions.”
The guidelines grade the evidence recommendations using the American College of Physicians’ clinical practice guidelines grading system. All of the ACP recommendations on EOL care are considered strong recommendations, meaning that benefits clearly outweigh the risks. All of the EOL recommendations are considered to have moderate quality of evidence because most of the published literature is on patients with cancer.
Genetically modified carrots provide more calcium
Genetically modifying carrots to express increased levels of a gene that enables the transport of calcium across membranes of plant cells can make the vegetables a better source of calcium, said researchers at Baylor College of Medicine in Houston and the Vegetable and Fruit Improvement Center at Texas A&M University in a report that appears today in the Proceedings of the National Academy of Sciences.
"Slightly altering the gene (sCAX1) to make it a more active transporter allows for increased bioavailable calcium in the carrots- ,” said Dr. Kendal Hirschi, professor of pediatrics-nutrition and principal investigator of the study conducted at the USDA/ARS Children’s Nutrition Research Center at BCM in cooperation with Texas Children’s Hospital.
In an initial study in mice, researchers found that those who were fed the carrots with the altered gene could get the same amount of calcium as those who ate twice the amount of normal carrots. In a study in 30 human adults, those who ate the modified carrots absorbed 41 percent more calcium than did those who ate the unmodified carrots.
"These carrots were grown in carefully monitored and controlled environments,” said Hirschi. "Much more research needs to be conducted before this would be available to consumers.”
Hirschi emphasizes that there is no magic food that will solve all nutritional problems, and that proper food and exercise are still necessary. However, further developments in this area of research could allow for more nutrients in fruits and vegetables and lead to improved health.
Osteoporosis, one of the world’s most prevalent nutritional disorders, is a disease that reduces bone mineral density in the body. Doctors usually prescribe more calcium and better calcium uptake as one solution to treat the disease. Increasing levels of calcium absorption from foods would have a significant global impact on this disease.
With physicians and nutrition experts recommending a vegetable-based diet for health, increasing the calcium that can be absorbed from plant-based food will become increasingly important, Hirschi said.
Others who participated in the study included Jay Morris, Keli M. Hawthorne, Tim Hotze and Dr. Steven A. Abrams, all of BCM.
Funding for this research came from the National Institutes of Health, the Vegetable and Fruit Improvement Center at Texas A&M University and the USDA/ARS Children’s Nutrition Research Center at Baylor College of Medicine. This study is available on line at
Fossils reveal dinosaurs had teen sex
* 22:00 14 January 2008
* NewScientist.com news service
* Jeff Hecht
Dinosaurs did not wait to have sex – adolescent females, including Tyrannosaurus rex, started reproducing before they had finished growing to adult size, a new study shows.
The findings add to evidence that adolescence was the prime of life for dinosaurs.
Age at sexual maturity gives insight into the reproductive strategy and life history of species, but is far from obvious in fossils. Birds, the closest living relatives of dinosaurs, do not reproduce until they reach full adult size, as do small mammals. In contrast, living reptiles and large mammals reproduce while still growing.
A previous study discovered that dinosaurs called Oviraptors found brooding on fossil nests were not fully grown – showing that they bred early, like primitive reptiles. (Biology Letters, DOI: 10.1098/rsbl.2007.0254).
However, that was only one species of modest size – about 2 metres long and 30 kilograms in weight. Now three larger dinosaurs have been added to the list of early breeders, showing the trait was widespread.
Telltale bone
The evidence comes from medullary bone – a calcium-rich tissue that female birds form as a calcium reserve during egg-laying, which has been recently identified inside a leg bone of a fossilised Tyrannosaurus rex.
And now Sarah Werning of the University of California at Berkeley, US, and colleagues have identified medullary tissue in teenage specimens of two more dinosaurs, the predator Allosaurus and the plant-eating Tenontosaurus.
The fossilised tibia of a 10-year-old adolescent female Allosaurus, shows growth rings and the medullary bone which is laid down prior to egg-laying (Image: Andrew Lee/Ohio University)
Crucially, all three dinosaurs are known well enough that good data is available on their growth and population distribution. The team reports that the Tenontosaurus was 8 years old, the Allosaurus was 10, and the T. rex was 18 years old. None had reached full adult size.
That means dinosaur reproduction differed dramatically from that of their avian descendants. Birds are vulnerable when immature, so they put all their energy into growing to be ready for flight, and do not reproduce until after they reach full adult size, says Werning. Many wait for a year or more before breeding.
Extra years
In contrast, the big dinosaurs lived only 3 or 4 years after reaching full size. By starting reproduction while still growing, "they are adding a decade for reproduction", Andrew Lee, co-author of the study, now at the Ohio University College of Osteopathic Medicine, told New Scientist.
Lee notes that elephants do the same today, with females reaching sexual maturity at 15 years, although they do not reach full size until about the age of 50.
By covering a range of dinosaurs, the new study gets closer to the base of the dinosaur family tree, says Kristi Curry Rogers of Macalester College in Minnesota, a coauthor of the oviraptor paper. "It's a nice piece of work and helps create a good picture of the lives of dinosaurs."
Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0708903105)
Sexually-active gay men vulnerable to new, highly infectious bacteria
Sexually active gay men are many times more likely than others to acquire a new, highly antibiotic-resistant strain of the so-called MRSA bacteria widely know as the "superbug," a UCSF-led study shows.
The bacteria appear to be transmitted most easily through intimate sexual contact, but can spread through casual skin-to-skin contact or contact with contaminated surfaces. The scientists are concerned that it could soon gain ground in the general population.
The new strain of bacteria is closely related to the MRSA bacteria that have spread beyond hospital borders in recent years and caused outbreaks of severe skin and other infections. But the newly discovered microbe is resistant to many more front-line antibiotics. Both strains are technically known as MRSA USA300.
Like its less antibiotic-resistant sibling, the new multi-drug resistant microbe spreads easily through skin-to-skin contact, invading skin and tissue beneath the skin. Both strains cause abscesses and ulcerations that can progress rapidly to life-threatening infections.
"These multi-drug resistant infections often affect gay men at body sites in which skin-to-skin contact occurs during sexual activities," says Binh Diep, PhD, UCSF postdoctoral scientist at San Francisco General Hospital Medical Center and lead author of a report on the finding.
"But because the bacteria can be spread by more casual contact, we are also very concerned about a potential spread of this strain into the general population."
A good scrubbing with soap and water may be the most effective way to prevent skin-to-skin contact transmission, especially after sexual activities, Diep says.
The scientists did not address the cause of the increased risk among gay men, but suspect that sexual risk behaviors play a significant role.
The study is based on review of medical records from outpatient clinics in San Francisco and Boston as well as nine of 10 medical centers serving San Francisco.
The research appears in the January 14 early online edition of the "Annals of Internal Medicine." It will appear in the print edition February 19, along with a related editorial.
Diep considers the rapid rise in infections alarming. About one in 588 people living in San Francisco’s Castro district – a neighborhood with the highest number of gay residents in the country – are infected with the multi-drug resistant MRSA bacteria. About one in 3800 San Franciscans overall are infected – also a surprisingly high number, he says. These statistics come from the scientists’ study of MRSA samples previously collected from patients in nine medical centers serving San Francisco.
In a second part of the study based on patient medical charts, the scientists found that sexually active gay men in San Francisco are about 13 times more likely to be infected than the general population.
"The potential widespread dissemination of multi-resistant form of USA300 into the general population is alarming," he adds. The microbe is known as "multidrug-resistant, community-associated MRSA USA300." MRSA stands for methicillin-resistant Staphylococcus aureus. Until recently, MRSA bacteria were confined to hospitals, where extensive use of antibiotics has prompted highly resistant strains to evolve. The spread of multidrug resistant MRSA into communities, first reported by the UCSF team in 2006 (Lancet. 2006:367:731-9), has led to heightened concern.
The microbe studied here differs from the more familiar community-associated MRSA in that it is resistant not only to methicillin, but also resistant to a battery of normally effective, first-line antibiotics.
"Prompt diagnosis and the right treatment are crucial to prevent life-threatening infections and the spread of this bacteria to close contacts," says study author Henry Chambers, MD, UCSF professor of medicine at San Francisco General Hospital Medical Center and lead scientist of a large multi-centered clinical trial recently funded by the National Institute of Health to study treatment of community-associated MRSA infections.
The scientists conclude that research should be undertaken to explore the link between MRSA and unsafe sexual risk behaviors.
The study was largely funded by the Centers for Disease Control and Prevention and a Pfizer grant.
Coauthors on the paper and collaborators in the study are UCSF scientists Christopher J. Graber, MD, MPH; Francoise Perdreau-Remington, PhD; Tiffany HaiVan Phan, BA; and Heather Carleton, MPH, all at San Francisco General Hospital Medical Center.
Also: John Szumowski, MD, MPH at Beth Israel Deaconess Medical Center; Loren Miller, MD, MPH, at Harbor-UCLA Medical Center; Linda Han, MD, at State Laboratory Institute, Jamaica Plain, Mass.; Jason Chen, BA; Felice Lin, BA; Jessica Lin, BA; and George Sensabaugh, DCrim, all of the School of Public Health, UC Berkeley; Linda McDougal, MS, and Fred Tenover, PhD, both at the Centers for Disease Control and Prevention; Daniel Cohen, MD, Fenway Community Health, Boston; and Kenneth Mayer, PhD, Brown University/Miriam Hospital, Rhode Island.