 |
|
Indiana U scientists uncover potential key to better drugs to fight toxoplasmosis parasite
June 19, 2008INDIANAPOLIS - Discoveries by Indiana University School of Medicine scientists have opened a promising door to new drugs for toxoplasmosis and other parasites that now can evade treatments by turning dormant in the body.
Their findings help explain how the parasite that causes toxoplasmosis transforms into a cyst form that resists drugs and the body's immune system, yet can emerge from its dormant state to strike when a patient's immune system is weakened.
Led by William J. Sullivan Jr., Ph.D., assistant professor of pharmacology and toxicology, and Ronald C. Wek, Ph.D., professor of biochemistry and molecular biology, the research team found a cellular signaling system that takes hold when the parasite is stressed, enabling it to transform into the cyst surrounded by a protective barrier.
The signaling system identified by the IU team could serve as a target to block the transformation into the cyst form or to attack the parasite while in the cyst form. Their report was published in the June 13 issue of the Journal of Biological Chemistry.
The Toxoplasma gondii parasite converts from an active state to the inactive cyst state when it is stressed, for example, by heat from fever. Stress response mechanisms have been well studied in yeast and other organisms, but the pathways used by the toxoplasmosis parasite had not been determined.
"We found a cellular signal that appears to put the parasite to sleep, which in turn tells us something new about how opportunistic pathogens such as Toxoplasma awaken to cause disease during immunosuppression," said Dr. Sullivan.
An estimated 60 million people in the United States are infected with the toxoplasmosis parasite, but for most infection produces flu-like symptoms or no symptoms at all. However, for people with immune system problems - such as those undergoing chemotherapy or people with AIDS - the disease can cause serious effects including lung problems, blurred vision and seizures. Also, infants born to mothers who are infected during or shortly before pregnancy are at risk for severe complications, miscarriages or stillbirths.
Medications to treat Toxoplasma gondii are effective but too toxic for extended use, and they don't affect the cyst form, said Dr. Sullivan.
"A healthy immune system can keep this parasite in the cyst state. Without a healthy immune system, this organism can run rampant," said Dr. Sullivan. "This can be a very serious problem for people with AIDS."
The discovery linking this stress-response mechanism to cyst formation and maintenance not only offers a possible target for new drugs, but it could also lead to a preventative vaccine - for animals.
The Toxoplasma gondii parasite can infect most animals and birds, but it reproduces in cats, which can shed the parasite in their feces. Humans can be infected through contact with the infected feces or litter. People can also become infected by consuming undercooked meat.
A vaccine to prevent infection in cats and livestock could prevent a significant proportion of human infections, Dr. Sullivan said.
Indiana University
The signaling system identified by the IU team could serve as a target to block the transformation into the cyst form or to attack the parasite while in the cyst form. Their report was published in the June 13 issue of the Journal of Biological Chemistry.
The Toxoplasma gondii parasite converts from an active state to the inactive cyst state when it is stressed, for example, by heat from fever. Stress response mechanisms have been well studied in yeast and other organisms, but the pathways used by the toxoplasmosis parasite had not been determined.
"We found a cellular signal that appears to put the parasite to sleep, which in turn tells us something new about how opportunistic pathogens such as Toxoplasma awaken to cause disease during immunosuppression," said Dr. Sullivan.
An estimated 60 million people in the United States are infected with the toxoplasmosis parasite, but for most infection produces flu-like symptoms or no symptoms at all. However, for people with immune system problems - such as those undergoing chemotherapy or people with AIDS - the disease can cause serious effects including lung problems, blurred vision and seizures. Also, infants born to mothers who are infected during or shortly before pregnancy are at risk for severe complications, miscarriages or stillbirths.
Medications to treat Toxoplasma gondii are effective but too toxic for extended use, and they don't affect the cyst form, said Dr. Sullivan.
"A healthy immune system can keep this parasite in the cyst state. Without a healthy immune system, this organism can run rampant," said Dr. Sullivan. "This can be a very serious problem for people with AIDS."
The discovery linking this stress-response mechanism to cyst formation and maintenance not only offers a possible target for new drugs, but it could also lead to a preventative vaccine - for animals.
The Toxoplasma gondii parasite can infect most animals and birds, but it reproduces in cats, which can shed the parasite in their feces. Humans can be infected through contact with the infected feces or litter. People can also become infected by consuming undercooked meat.
A vaccine to prevent infection in cats and livestock could prevent a significant proportion of human infections, Dr. Sullivan said.
Indiana University
Toxoplasmosis Current Events and Toxoplasmosis News RSSLocking Parasites in Host Cell Could Be New Way to Fight Malaria, Penn Study Shows
Researchers at the University of Pennsylvania have discovered that parasites hijack host-cell proteins to ensure their survival and proliferation, suggesting new ways to control the diseases they cause.
Research supports toxoplasmosis link to schizophrenia
Scientists have discovered how the toxoplasmosis parasite may trigger the development of schizophrenia and other bipolar disorders.
Parasites that live inside cells use loophole to thwart immune system
St. Jude Children's Research Hospital scientists have discovered a mechanism by which intracellular pathogens can shut down one of the body's key chemical weapons against them: nitric oxide.
Persistent bacterial infection exploits killing machinery of immune cells
A new study reveals an important and newly discovered pathway used by disease-causing bacteria to evade the host immune system and survive and grow within the very cells meant to destroy them. This discovery may lead to new treatments and vaccines for tuberculosis (TB) and certain other chronic bacterial and parasitic infections.
Purifying parasites with light
Researchers have developed a clever method to purify parasitic organisms from their host cells, which will allow for more detailed proteomic studies and a deeper insight into the biology of organisms that cause millions of cases of disease each year.
Toxoplasmosis found more severe in Brazil compared to Europe
Newborns in Brazil are more susceptible to toxoplasmosis than those in Europe, according to a recent study. Researchers based in Austria, Brazil, Denmark, France, Italy, Poland, Sweden, and the United Kingdom studied the disease's ocular effects in children from birth to four years of age.
Disrupting common parasites' ability to 'talk' to each other reduces infection
One of the most common human parasites, Toxoplasma gondii, uses a hormone lifted from the plant world to decide when to increase its numbers and when to remain dormant, researchers at Washington University School of Medicine in St. Louis have found.
Poor Americans in the United States suffer hidden burden of parasitic and other neglected diseases
Large numbers of the poorest Americans living in the United States are suffering from some of the same parasitic infections that affect the poor in Africa, Asia, and Latin America, says the Editor-in-Chief of PLoS Neglected Tropical Diseases.
Toxoplasmosis infection trick revealed by scientists
Toxoplasmosis is a parasitic disease, primarily carried by cats. It is transmitted to humans by eating undercooked meat or through contact with cat faeces.
Single protein can determine severity of toxoplasma infections
The unusual ability of the organism Toxoplasma to infect and reproduce inside almost all warm-blooded animals has led scientists to wonder about the tricks it uses so successfully to subvert the behavior of cells.
More Toxoplasmosis Current Events and Toxoplasmosis News Articles
 |
Toxoplasmosis: A Comprehensive Clinical Guide by David H. M. Joynson (Editor), Tim G. Wreghitt (Editor) This authoritative and comprehensive account looks at the reemergence of toxoplasmosis as a significant and potentially fatal infection. A team of acknowledged international experts review the latest diagnostic techniques, and the management of infection in pregnant women, neonates, the eye, transplant and other immunosuppressed patients, including AIDS patients. The contentious issue of the role of screening during pregnancy and in the newborn is covered in depth. The introductory chapters on biology, immunology, and epidemiology of the infection provide essential background to understanding the clinical disease. The full range of treatment strategies are presented in an easily accessible form. |
 |
Giant Microbes Toxoplasmosis (Toxoplasma gondii) Plush by Giant Microbes Don't play with cat scat. 'Nuff said. GIANTmicrobes(R) Original (5-7" plush doll) |
 |
Storm and Thunder (Toxoplasmosis) Pantaleimon & The Bricoleur (Primary Contributor) |
 |
2 Classic Red Panda Adventures Old Time Radio Broadcasts on DVD (over 52 minutes running time) This unique old time radio DVD collectible features 2 digitized reels of classic Red Panda Adventures radio broadcasts and over 52 minutes of total running time on 1 DVD. Take a journey back through radio broadcasting history with this large audio library of OTR memorabilia. The golden age of old time radio has been rescued, digitized, and packaged into a gift set that any classic radio lover can appreciate. The DVD opens and plays in a computer DVD drive and the collector can listen to the audio on a MP3 player, DVD/MP3-compatible car stereo, computer, MP3-compatible DVD player, or just compile favorites onto CD for greater user flexibility. |
 |
Toxoplasmosis (Toxoplasma gondii) GIANTMicrobes Original by GIANTMicrobes, Inc. Toxoplasmosis (Toxoplasma gondii) GIANTMicrobes Original - Don't play with cat scat. 'Nuff said. This item is a GIANTmicrobes(R) Original (5-7" plush doll). GIANTMicrobes Original - GIANTMicrobes by Drew Oliver! [Product ID: GM-TOXOP1] [SKU: GMUS-PD-0756] [UPC: 874665008240] |
 |
Toxoplasmosis of Animals and Humans, Second Edition by J. P. Dubey (Author) Found worldwide from Alaska to Australasia, Toxoplasma gondii knows no geographic boundaries. The protozoan is the source of one of the most common parasitic infections in humans, livestock, companion animals, and wildlife, and has gained notoriety with its inclusion on the list of potential bioterrorism microbes. In the two decades since the publication of the first edition of Toxoplasmosis of Animals and Humans there has been an explosion of knowledge concerning T. gondii and toxoplasmosis. Still used extensively as a cell model, its genome has recently been published making it a subject of even greater scientific interest. Keeping the organizational style that made the previous edition so popular and usable, this second edition has been completely revised and... |
|
Human Toxoplasmosis (Oxford Medical Publications) by Darrel O. Ho-Yen (Editor), Alex W. L. Joss (Editor) Toxoplasmosis, a world-wide infection of animals and humans, may produce severe congenital abnormalities in pregnancy, while among the immunocompromised (malignancies, organ transplant, or human immunodeficiency virus infection), death may result. Toxoplasmosis is likely to become more common, and those who manage high-risk patients must be aware of the infection, and the latest techniques for minimizing its serious complications. Women need testing consistent with medical defence advice as well as advice on avoiding infection. This comprehensive volume contains chapters on the history of toxoplasmosis, its clinical features and life cycle, diagnosis management, prevention, and possible future developments. Animal infection, with its important economic and human implications, is... | |
|
Genetic divergence of Toxoplasma gondii strains associated with ocular toxoplasmosis, Brazil.(RESEARCH)(infectious diseases research)(includes statistical ... article from: Emerging Infectious Diseases by Asis Khan (Author), Catherine Jordan (Author), Cristina Muccioli (Author), Adriana L. Vallochi (Author), Luiz V. Rizzo (Author), Rubens, Jr. Belfort (Author), Ricardo W.A. Vitor (Author), Claudio Silveira (Author), L. David Sibley (Author) This digital document is an article from Emerging Infectious Diseases, published by Thomson Gale on June 1, 2006. The length of the article is 5925 words. The page length shown above is based on a typical 300-word page. The article is delivered in HTML format and is available in your Amazon.com Digital Locker immediately after purchase. You can view it with any web browser. Citation Details Title: Genetic divergence of Toxoplasma gondii strains associated with ocular toxoplasmosis, Brazil.(RESEARCH)(infectious diseases research)(includes statistical table) Author: Asis Khan Publication: Emerging Infectious Diseases (Magazine/Journal) Date: June 1, 2006 Publisher: Thomson Gale Volume: 12 Issue: 6 Page: 942(8) Distributed by Thomson... | |
|
HUMAN TOXOPLASMOSIS: CLINICAL DATA AND MICROBIOLOGY by Luiz G. Spoladore (Author), Illustrated (Illustrator) As new; color plates & drawings, 152 pp. | |
 |
21st Century Complete Medical Guide to Toxoplasmosis and Related Parasitic Diseases: Authoritative Government Documents, Clinical References, and Practical Information for Patients and Physicians by PM Medical Health News (Author) This up-to-date electronic book on CD-ROM provides the best collection available anywhere of official Federal government information and documents on the subject of toxoplasmosis. This CD-ROM uses next-generation search technology that allows complete indexing and makes all files on the disc fully searchable. For patients, practical information is provided in clearly written patient education documents. For medical professionals, doctor reference tools and texts have detailed technical information and clinical background material. This thoroughly researched collection presents vital information from many authoritative sources: National Institutes of Health (NIH), Centers for Disease Control (CDC), the Combined Health Information Database (CHID), the Food and Drug Administration... |
| © 2009 BrightSurf.com |