September 11, 2008, 8:49 PM CT
Nano-Sized'Cargo Ships' to Destroy Tumors
UCSD graduate student Ji-Ho Park holds a vial containing the nanometer-sized cargo ships, composed of a magnetic nanoparticle, a fluorescent quantum dot and an anti-cancer drug molecule that will be left on the site of the tumor.
Credit: Luo Gu, UCSD
Researchers have developed nanometer-sized 'cargo ships' that can sail throughout the body via the bloodstream without immediate detection from the body's immune radar system and ferry their cargo of anti-cancer drugs and markers into tumors that might otherwise go untreated or undetected.
In a forthcoming issue of the Gera number of-based chemistry journal Angewandte Chemie, researchers at UC San Diego, UC Santa Barbara and MIT report that their nano-cargo-ship system integrates therapeutic and diagnostic functions into a single device that avoids rapid removal by the body's natural immune system. Their paper is now accessible in an early online version here.
"The idea involves encapsulating imaging agents and drugs into a protective 'mother ship' that evades the natural processes that normally would remove these payloads if they were unprotected," said Michael Sailor, a professor of chemistry and biochemistry at UCSD who headed the team of chemists, biologists and engineers that turned the fanciful concept into reality. "These mother ships are only 50 nanometers in diameter, or 1,000 times smaller than the diameter of a human hair, and are equipped with an array of molecules on their surfaces that enable them to find and penetrate tumor cells in the body".........
Posted by: Janet Read more Source
September 11, 2008, 8:29 PM CT
Mad cow disease also caused by genetic mutation
A. Richt, Regents Distinguished Professor of Diagnostic Medicine and Pathobiology at Kansas State University's College of Veterinary Medicine.
Credit: Juergen Richt
New findings about the causes of mad cow disease show that sometimes it may be genetic.
"We now know it's also in the genes of cattle," said Juergen A. Richt, Regents Distinguished Professor of Diagnostic Medicine and Pathobiology at Kansas State University's College of Veterinary Medicine.
Until several years ago, Richt said, it was thought that the cattle prion disease bovine spongiform encephalopathy -- also called BSE or mad cow disease -- was a foodborne disease. But his team's new findings suggest that mad cow disease also is caused by a genetic mutation within a gene called Prion Protein Gene. Prion proteins are proteins expressed abundantly in the brain and immune cells of mammals.
The research shows, for the first time, that a 10-year-old cow from Alabama with an atypical form of bovine spongiform encephalopathy had the same type of prion protein gene mutation as found in human patients with the genetic form of Creutzfeldt-Jakob disease, also called genetic CJD for short. Besides having a genetic origin, other human forms of prion diseases can be sporadic, as in sporadic CJD, as well as foodborne. That is, they are contracted when people eat products contaminated with mad cow disease. This form of Creutzfeldt-Jakob disease is called variant CJD.........
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September 10, 2008, 10:13 PM CT
Bleeding gums linked to heart disease
Bleeding gums and poor dental hygiene can end up causing heart disease, researchers heard today (Thursday 11 September2008) at the Society for General Microbiology's Autumn meeting being held this week at Trinity College, Dublin.
People with poor dental hygiene and those who don't brush their teeth regularly end up with bleeding gums, which provide an entry to the bloodstream for up to 700 different types of bacteria found in our mouths. This increases the risk of having a heart attack, as per microbiologists from the University of Bristol and the Royal College of Surgeons in Ireland.
"The mouth is probably the dirtiest place in the human body," said Dr Steve Kerrigan from the Royal College of Surgeons in Dublin, Ireland. "If you have an open blood vessel from bleeding gums, bacteria will gain entry to your bloodstream. When bacteria get into the bloodstream they encounter tiny fragments called platelets that clot blood when you get a cut. By sticking to the platelets bacteria cause them to clot inside the blood vessel, partially blocking it. This prevents the blood flow back to the heart and we run the risk of suffering a heart attack".
The only therapy for this type of disease is aggressive antibiotic treatment, but with the increasing problem of multiple drug resistant bacteria, this option is becoming short lived.........
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September 10, 2008, 10:11 PM CT
Immaturity of the brain may cause schizophrenia
The underdevelopment of a specific region in the brain may lead to schizophrenia in individuals. As per research published recently in BioMed Central's open access journal Molecular Brain
, dentate gyrus, which is located in the hippocampus in the brain and believed to be responsible for working memory and mood regulation, remained immature in an animal model of schizophrenia.
Professor Tsuyoshi Miyakawa of Fujita Health University, National Institute for Physiological Sciences (NIPS), and Kyoto University led a research team in Japan, with support from the CREST program of Japan Science and Technology Agency (JST). First, the team investigated behaviors by conducting a systematic and well-defined behavioral test battery with alpha-CaMKII mutant mice, an animal model of schizophrenia. These mice showed abnormal behaviors similar to those of schizophrenic patients. Next, the team found the dentate gyrus neurons in hippocampus of the brain of these mice were not matured morphologically and physiologically. By a gene expression analysis, changes of gene expression correlation to the maturation of dentate gyrus neurons were also found in the brains of schizophrenic patients. Taken together, the immaturity of the dentate gyrus may be an underlying cause for schizophrenia.........
Posted by: Daniel Read more Source
September 10, 2008, 10:05 PM CT
Killing bacteria isn't enough to restore immune function
A bacterial molecule that initially signals to animals that they have been invaded must be wiped out by a special enzyme before an infected animal can regain full health, scientists at UT Southwestern Medical Center have found.
Using a genetically engineered mouse model, the team observed that simply eradicating the infection-causing bug isn't enough to restore an animal's immune function. Lipopolysaccharide, or LPS, the dominant bacterial "signal" molecule that heralds the invasion, must also be inactivated. The findings are to appear online Sept. 11 in Cell Host & Microbe.
"We think this is the first evidence that killing the causative agent of a bacterial infection isn't enough for an animal to recover fully," said Dr. Robert Munford, professor of internal medicine and microbiology, and senior author of the study. "You've got to get rid of this molecule that the host is responding to or else its immune system remains suppressed."
By sensing and responding to LPS, animals mobilize their defenses to attack and kill the bacteria. This immune response also causes inflammation in the host. For a few days after the infection begins, however, an animal's ability to sense the bacteria is turned down, presumably to prevent further inflammation. In the current study, the scientists observed that mice didn't recover from this "tolerant" period unless the LPS was inactivated by acyloxyacyl hydrolase, an enzyme discovered in 1983 by Dr. Munford and Dr. Catherine Hall, now an assistant professor of internal medicine at UT Southwestern.........
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September 10, 2008, 10:03 PM CT
Abuse of painkillers can predispose to addiction
No child aspires to a lifetime of addiction. But their brains might. In new research to appear online in the journal Neuropsychopharmacology
this week, Rockefeller University scientists reveal that adolescent brains exposed to the painkiller Oxycontin can sustain lifelong and permanent changes in their reward system changes that increase the drug's euphoric properties and make such adolescents more vulnerable to the drug's effects later in adulthood.
The research, led by Mary Jeanne Kreek, head of the Laboratory of the Biology of Addictive Diseases, is the first to directly compare levels of the chemical dopamine in adolescent and adult mice in response to increasing doses of the painkiller. Kreek, first author Yong Zhang, a research associate in the lab, and their colleagues observed that adolescent mice self-administered Oxycontin less frequently than adults, suggesting that adolescents were more sensitive to its rewarding effects. These adolescent mice, when re-exposed to a low dose of the drug as adults, also had significantly higher dopamine levels in the brain's reward center in comparison to adult mice newly exposed to the drug.
"Together, these results suggest that adolescents who abuse prescription pain killers may be tuning their brain to a lifelong battle with opiate addiction if they re-exposed themselves to the drug as adults," says Kreek. "The neurobiological changes seem to sensitize the brain to the drug's powerfully rewarding properties."........
Posted by: JoAnn Read more Source
September 10, 2008, 8:43 PM CT
Gap junction protein vital to successful pregnancy
Deleting the Cx43 gene in the uterus immediately after pregnancy in mice dramatically reduced blood vessel growth and in most cases prevented successful pregnancy. The image on the left shows normal blood vessel growth in the mouse uterus following pregnancy. On the right, a uterus lacking Cx43.
Credit: Photo by Mary J. Laws
Scientists studying a critical stage of pregnancy implantation of the embryo in the uterus have found a protein that is vital to the growth of new blood vessels that sustain the embryo. Without this protein, which is produced in higher quantities in the presence of estrogen, the embryo is unlikely to survive.
This is the first study to detail the mechanism by which the steroid hormone estrogen spurs cell differentiation and blood-vessel growth in the uterus during pregnancy, the scientists report.
The findings, from scientists at the University of Illinois, Emory University, Baylor College of Medicine and New York University, appear in the journal Development
Connexin 43 (Cx43) belongs to a family of proteins that form junctions between cells that regulate the flow of ions and small signaling molecules from cell to cell. At the time of embryo implantation, this gap junction protein is essential to the rapid growth of new blood vessels needed to support the development of the embryo and allow it to implant in the uterine wall, the scientists discovered.
The scientists chose to study Cx43 after analyzing genes that are activated in the presence of estrogen in uterine cells. They observed that Cx43 was prominent among the genes whose expression was increased in cells after exposure to estrogen.........
Posted by: Emily Read more Source
September 10, 2008, 7:28 PM CT
Individuals vary their immune response
Is it always good to respond maximally when pathogens or disease strike, or should individuals vary their immune response to balance immediate and future costs? This is the question evolutionary physiologists Oliver Love, Katrina Salvante, James Dale, and Tony Williams asked when they examined how a simple immune response varied at different life stages across the life-span of individual zebra finches (Taeniopygia guttata
), as per a research findings reported in the recent issue of the American Naturalist
When transitioning from nest-bound juveniles to adults, female immune responses matured slowly whereas males showed dramatic variation potentially due to the costs of molting into their colorful sexually dimorphic plumage. Adult males showed little variation in immune response despite changes in resource quality. Likewise, when females laid eggs under high-quality resource conditions, immune responses were also consistent with those during non-breeding and similar to male responses. However, when laying on reduced resources females reduced their immune response and their reproductive output consistent with a facultative (resource-driven) effect of reproductive effort on immunity. Moreover, even under high-resource conditions during the chick-rearing stage mothers showed reduced immune responses in comparison to fathers suggesting a residual energetic cost of egg-laying. Perhaps most importantly, immune responses of juveniles of both sexes did not predict their subsequent adult responses. Immune responses of adult females were only predictable when the quality of the environment remained constant; as soon as conditions deteriorated, individual females mandatory flexibility in both the immune and reproductive systems. However, the degree of flexibility came at a cost as only individuals with high immune responses as non-breeders had the capacity to reduce responses when times became tough. These results underlie the fact that immunity is a highly plastic trait that can be modulated in a sex- and context-dependent manner. Given the need for individual flexibility in the immune system, this suggests that an immune response at one stage may provide limited information about immune response at future stages.........
Posted by: Janet Read more Source
September 9, 2008, 10:04 PM CT
Older adults can take medicines more safely
Elderly adults may be better able to comply with medicine regimens by working with providers to fill out simple paper tables that track what they take and when they take it. Recent experiments observed that use of a "medtable" may help to prevent medication-related problems. A report appears in the recent issue of Journal of Experimental Psychology: Applied,
published by the American Psychological Association.
As they age, people often take several different prescription medications. Yet about half of elderly adults are found to take medicine incorrectly and up to one in three of their hospital admissions is blamed on faulty medicine use. Weak collaboration with health-care providers, along with cognitive problems and lower health literacy, are viewed as contributors.
Psychology experts at the University of Illinois at Urbana-Champaign led by Daniel Morrow, PhD, observed that when pairs of elderly adults filled out a written matrix listing medications and instructions by days and times to take them, they solved medication-related problems more efficiently and accurately, particularly for the complex medicine schedules increasingly common among elderly adults.
In Experiment 1, 96 participants averaging 69 years in age were randomly assigned to the role of patient or provider. These pairs were randomly assigned to use a pre-designed medtable, a blank piece of paper or no aid. To simulate real life, the scientists varied information about both medicine and patient.........
Posted by: Janet Read more Source
September 9, 2008, 9:29 PM CT
Early stage colon cancer and gatekeeper gene
The absence or inactivation of the RUNX3 gatekeeper gene paves the way for the growth and development of colon cancer, Singapore researchers report in the Sept. issue of the journal Cancer Cell
Prior studies have shown that RUNX3 plays a role in gastric, breast, lung and bladder cancers.
The inactivation of RUNX3 occurs at a very early stage of colon cancer, as per the Singapore scientists' studies with human tissue samples and animal models.
Because the inactivation of RUNX3 is relatively easy to detect, and it is possible that inactivated RUNX3 can be reactivated, this new research may prove to be a crucial step in the development of an early diagnostic test as well as a therapeutic target for colon cancer.
Previous to these new findings, researchers knew that a tumor suppressor gene called APC is disrupted in most cases of human colon cancer. APC disruption activates bete-catenin and TCF4, a protein complex that plays an important role in cancer development. For decades, this has been considered the molecular basis for colon cancer.
These latest findings are the first to show that the activity of beta- catenin/TCF4 also is inhibited by RUNX3.
The Singapore researchers are based at the National University of Singapore's (NUS) Yong Loo Lin School of Medicine and the Institute of Molecular and Cell Biology (IMCB), one of the 14 research institutes under the country's Agency for Science, Technology and Research (A*STAR).........
Posted by: Sue Read more Source