Scientific data in various fields of human endeavor. Interesting user friendly presentation of articles in sciences both recent and in the distant past
Science (July 11, 2010) — A South Dakota State University scientist’s research shows an extract made from a food plant in the Brassica family was effective in alleviating signs of ulcerative colitis, an inflammatory bowel condition, in mice.
The ongoing study by associate professor Moul Dey in SDSU’s Department of Health and Nutritional Sciences — funded by the National Institutes of Health — moves on now to examine the potential use of the plant extract against colon cancer.
“There is an established link between ulcerative colitis and colon cancer. People who have ulcerative colitis are at significantly higher risk to have colon cancer,” Dey said. “Whether this plant extract might help with colon cancer symptoms directly or perhaps delay the onset of colon cancer in ulcerative colitis patients, we don’t know the answers to those questions, but it is something we would like to look into.”
Dey and her team will carry out that research over the next two and a half years as she continues her work on a Pathway to Independence award for promising young scientists. That National Institutes of Health grant of nearly $900,000 over five years was awarded to Dey for work she began as a researcher at Rutgers University.
As a researcher at Rutgers starting in 2004, Dey developed a mammalian cell-based screening platform and screened nearly 3,000 plant extracts for potential anti-inflammatory activity. A plant-derived compound called Phenethylisothiocyanate, or PEITC, was one among others that showed potential anti-inflammatory activities. The NIH funded Dey’s proposal to study it further.
PEITC is found in the Brassica genus of plants, which includes cabbage, cauliflower, watercress and broccoli. Barbarea verna, also known as upland cress or early wintercress, a herb that is used in salads, soups, and garnishes, is one of the richest sources of dietary PEITC in Dey’s study.
Scientists had already studied the compound for its anticarcinogenic properties prior to Dey’s investigation on its anti-inflammatory activities.
“I tested this substance in a mouse model that is already established and widely used. What we found is that it not only alleviates several clinical signs of ulcerative colitis — for example, it attenuates the damage that occurs in the colon tissues and colon epithelium, as well as the clinical signs like diarrhea and blood in stool. The weight loss is a major sign in colitis and that was alleviated, too.” However, she noted that although mammalian animal models are routinely used for an initial test of biological effects of compounds targeted for potential human use, obtained results may not always repeat in humans.
Inflammatory bowel disease, or IBD, is a set of chronic and relapsing inflammatory disorders of the intestine that affects an estimated 2 million people annually in the United States. Two common forms of IBD are Crohn’s disease and ulcerative colitis.
When Dey and her colleagues looked into the mechanism by which the compound might be working against IBD, they found that it downregulates many of the genes that are known to be upregulated in human patients with colitis. That means the compound acts on cells to decrease the quantity of cellular components such as specific proteins that are produced abundantly in colitis patients. One such protein is a novel transcription factor. Transcription factors are one of the groups of proteins that read and interpret the genetic “blueprint” in the DNA.
“We are excited about these findings and our next step would be to see how this plant and the compounds from this plant may be effective against colon cancer, alleviating colon cancer or preventing the onset of colon cancer,” Dey said.
“I am not a cancer biologist per se. My interests are really in cellular mechanisms of inflammatory diseases. The only reason we are going to study colon cancer in this particular project is because ulcerative colitis is very closely linked to colon cancer.”
Colon carcinogenesis is highly preventable, yet colon cancer has one of the highest death rates among all cancers due to typical late diagnosis.
Since people already eat vegetables containing PEITC, there is a long history of human consumption with no adverse effects.
“Obviously the dose we are testing is significantly higher than what we eat in a vegetable, but we have done multiple safety tests and found that this dose is safe in animals,” Dey said.
Dey has no plans to test the extract in humans as part of the current project, but said additional tests would be required if the extract leads to new drugs or treatments in humans.
Dey’s co-authors are Peter Kuhn of Phytomedics Inc., of Jamesburg, N.J.; David Ribnicky, Kenneth Reuhl and Ilya Raskin of Rutgers University, and VummidiGiridhar Premkumar, who is currently at University of Cincinnati
Science(June 28, 2010) — As you go about your day-to-day activities, tiny bubbles of nitrogen come and go inside your tissues. This is not a problem unless you happen to experience large changes in ambient pressure, such as those encountered by scuba divers and astronauts. During large, fast pressure drops, these bubbles can grow and lead to decompression sickness, popularly known as “the bends.”
A study in the Journal of Chemical Physics, which is published by the American Institute of Physics (AIP), may provide a physical basis for the existence of these bubbles, and could be useful in understanding decompression sickness.
A physiological model that accounts for these bubbles is needed both to protect against and to treat decompression sickness. There is a problem though. “These bubbles should not exist,” says author Saul Goldman of the University of Guelph in Ontario, Canada.
Because they are believed to be composed mostly of nitrogen, while the surrounding atmosphere consists of both nitrogen and oxygen, the pressure of the bubbles should be less than that of the surrounding atmosphere. But if this were so, they would collapse.
“We need to account for their apparent continuous existence in tissues in spite of this putative pressure imbalance,” says Goldman.
If, as is widely believed, decompression sickness is the result of the growth of pre-existing gas bubbles in tissues, those bubbles must be sufficiently stable to have non-negligible half-lives. The proposed explanation involves modeling body tissues as soft elastic materials that have some degree of rigidity. Previous models have focused on bubble formation in simple liquids, which differ from elastic materials in having no rigidity.
Using the soft-elastic tissue model, Goldman finds pockets of reduced pressure in which nitrogen bubbles can form and have enough stability to account for a continuous presence of tiny bubbles that can expand when the ambient pressure drops. Tribonucleation, the phenomenon of formation of new gas bubbles when submerged surfaces separate rapidly, provides the physical mechanism for formation of new gas bubbles in solution. The rapid separation of adhering surfaces results in momentary negative pressures at the plane of separation. Therefore, while these tiny bubbles in elastic media are metastable, and do not last indefinitely, they are replaced periodically. According to this picture, tribonucleation is the source, and finite half-lives the sink, for the continuous generation and loss small gas bubbles in tissues.
Science (June 28, 2010) — For people with hypertension, eating dark chocolate can significantly reduce blood pressure. Researchers writing in the open access journal BMC Medicine combined the results of 15 studies into the effects of flavanols, the compounds in chocolate which cause dilation of blood vessels, on blood pressure.
Dr Karin Ried worked with a team of researchers from the University of Adelaide, Australia, to conduct the analysis. She said, “Flavanols have been shown to increase the formation of endothelial nitric oxide, which promotes vasodilation and consequently may lower blood pressure. There have, however, been conflicting results as to the real-life effects of eating chocolate. We’ve found that consumption can significantly, albeit modestly, reduce blood pressure for people with high blood pressure but not for people with normal blood pressure.”
The pressure reduction seen in the combined results for people with hypertension, 5mm Hg systolic, may be clinically relevant — it is comparable to the known effects of 30 daily minutes of physical activity (4-9mm Hg) and could theoretically reduce the risk of a cardiovascular event by about 20% over five years.
The researchers are cautious, however, “The practicability of chocolate or cocoa drinks as long-term treatment is questionable,” said Dr Ried.
October 1, 2007 — A nephrologist has found that a specialized type of anti-rejection therapy using intravenous immunoglobulin can make kidney transplants possible for patients with high ‘anti-donor’ antibodies. 25 to 30 percent of patients on the kidney transplant list could benefit from this therapy. Tissue compatibility issues exist with any organ transplant, but the risk is greatly increased for those with high exposure to antigens received through blood transfusions, previous transplantation, or even pregnancy.
Seventy-thousand Americans are waiting for a kidney transplant. A third of them are parked on dialysis because their antibody levels are too high for a transplant. But that’s no longer a barrier for some people.
“I used to just sit around and throw up,” says former dialysis patient Soraya Kohanzadeh.
Dialysis is something Kohanzadeh would rather forget, but if telling her story saves lives, it’s worth it.
Kohanzadeh — like many kidney failure patients — developed high levels of “anti-donor” antibodies through blood transfusions. Her highly sensitized immune system would likely reject any donated kidney.
“Essentially, she would have a very short, sick life on dialysis,” says Joan Lando, Kohanzadeh’s mother.
But Kohanzadeh is no longer here, thanks to intravenous immunoglobulin therapy or IVIG. Here’s how it works: during dialysis, patients are given blood containing a mix of immunoglobulins, which “turn-off” the anti-donor antibodies’ attack response without suppressing the patient’s immune system.
“A significant other comes forward, donates an organ, and there’s an incompatibility there. We can treat the patient and remove those antibodies. Then the transplant can be done,” Stanley Jordan, M.D., director of nephrology at Cedars-Sinai Medical Center in Los Angeles.
More than a year after surgery, Lando’s kidney keeps her daughter alive.
“It was sort of shocking to think I wasn’t going to have to be sick forever,” Kohanzadeh says.
Through their website, this mother-daughter team works to spread the word of a little known therapy that could save thousands in need of a kidney. IVIG is covered by Medicare and can be used in both living and cadaver-donor transplants. Nearly 30 percent of patients on the kidney transplant list might benefit from this therapy.
Science (June 11, 2010) — Scientists are reporting the first evidence that a plastic antibody — an artificial version of the proteins produced by the body’s immune system to recognize and fight infections and foreign substances — works in the bloodstream of a living animal.
The discovery, they suggest in a report in the Journal of the American Chemical Society, is an advance toward medical use of simple plastic particles custom tailored to fight an array of troublesome “antigens.”
Those antigens include everything from disease-causing viruses and bacteria to the troublesome proteins that cause allergic reactions to plant pollen, house dust, certain foods, poison ivy, bee stings and other substances.
In the report, Kenneth Shea, Yu Hosino, and colleagues refer to previous research in which they developed a method for making plastic nanoparticles, barely 1/50,000th the width of a human hair, that mimic natural antibodies in their ability to latch onto an antigen. That antigen was melittin, the main toxin in bee venom. They make the antibody with molecular imprinting, a process similar to leaving a footprint in wet concrete. The scientists mixed melittin with small molecules called monomers, and then started a chemical reaction that links those building blocks into long chains, and makes them solidify. When the plastic dots hardened, the researchers leached the poison out. That left the nanoparticles with tiny toxin-shaped craters.
Their new research, together with Naoto Oku’s group of the University Shizuoka Japan, established that the plastic melittin antibodies worked like natural antibodies. The scientists gave lab mice lethal injections of melittin, which breaks open and kills cells. Animals that then immediately received an injection of the melittin-targeting plastic antibody showed a significantly higher survival rate than those that did not receive the nanoparticles. Such nanoparticles could be fabricated for a variety of targets, Shea says. “This opens the door to serious consideration for these nanoparticles in all applications where antibodies are used,” he adds.
Sourced and published by Henry Sapiecha 12th June 2010
Science (May 26, 2010) — A scientist at the University of Reading has become the first person in the world to be infected by a computer virus.
Dr Mark Gasson, from the School of Systems Engineering, contaminated a computer chip which had been inserted into his hand as part of research into human enhancement and the potential risks of implantable devices.
These results could have huge implications for implantable computing technologies used medically to improve health, such as heart pacemakers and cochlear implants, and as new applications are found to enhance healthy humans.
Dr Gasson says that as the technology behind these implants develops, they become more vulnerable to computer viruses.
“Our research shows that implantable technology has developed to the point where implants are capable of communicating, storing and manipulating data,” he said. “They are essentially mini computers. This means that, like mainstream computers, they can be infected by viruses and the technology will need to keep pace with this so that implants, including medical devices, can be safely used in the future.”
Dr Gasson will present his results next month at the IEEE International Symposium on Technology and Society in Australia, which he is also chairing.
A high-end Radio Frequency Identification (RFID) chip was implanted into Dr Gasson’s left hand last year. Less sophisticated RFID technology is used in shop security tags to prevent theft and to identify missing pets.
The chip has allowed him secure access to his University building and his mobile phone. It has also enabled him to be tracked and profiled. Once infected, the chip corrupted the main system used to communicate with it. Should other devices have been connected to the system, the virus would have been passed on.
Dr Gasson said: “By infecting my own implant with a computer virus we have demonstrated how advanced these technologies are becoming and also had a glimpse at the problems of tomorrow.
“Much like people with medical implants, after a year of having the implant, I very much feel that it is part of my body. While it is exciting to be the first person to become infected by a computer virus in this way, I found it a surprisingly violating experience because the implant is so intimately connected to me but the situation is potentially out of my control.
“I believe it is necessary to acknowledge that our next evolutionary step may well mean that we all become part machine as we look to enhance ourselves. Indeed we may find that there are significant social pressures to have implantable technologies, either because it becomes as much of a social norm as say mobile phones, or because we’ll be disadvantaged if we do not. However we must be mindful of the new threats this step brings.”
Sourced and published by Henry Sapiecha 28th May 2010
Science (Apr. 29, 2010) — It makes your skin crawl — a bug that crawls onto your lips while you sleep, drawn by the exhaled carbon dioxide, numbs your skin, bites, then gorges on your blood. And if that’s not insult enough, it promptly defecates on the wound-and passes on a potentially deadly disease.
Now Jean-Paul Paluzzi, a PhD candidate in biology at the University of Toronto Mississauga, believes that manipulating physiology to prevent the insects from leaving their messy calling card represents the best hope for stopping the transmission of the illness, known as Chagas’ disease.
“This is a disease of the poor,” says Paluzzi, who has visited parts of the world affected by the illness. “The bugs are found in makeshift homes with mud walls and palm tree-like ceilings. Unfortunately, the people of Central and South America that this affects don’t have sufficient voice to get help. Given that there are roughly 15 to 19 million people that are infected-a substantial proportion of that area’s population-it’s a disease that’s been neglected.”
Chagas’ disease is one of the major health problems in South and Central America and is spread by reduvid bugs, also known as “kissing bugs” because of their fondness for lips. The disease they transmit is caused by Trypanosoma cruzi, a parasite that lives in their gut. In the initial acute stage, symptoms are relatively mild, but as the disease progresses over several years, serious chronic symptoms can appear, such as heart disease and malformation of the intestines. Without treatment, it can be fatal. Currently, insecticide sprays are used to control insect populations, and anti-parasitic drugs are somewhat successful at treating acute infections.
Once the disease is chronic, it cannot be cured.
To make matters worse, kissing bugs are particularly “bloodthirsty.” In mosquitoes, which go through four distinct stages of development, only adult females feed on blood (and potentially transmit disease). This means that pest control methods need to target only one out of eight stages (when you include both sexes). But in kissing bugs, each sex feeds on blood through all fives stages of development. “So you have about a ten-fold greater chance of infection just because of the number of times that these insects have to feed,” says Paluzzi.
His research focuses on insect diuresis-more specifically, the genes and peptides that control how the kissing bug eliminates excess fluid in its gut after it gorges on blood. For the insect, the real prize in its meal is the red blood cells, while the water and salt is “excess baggage.” After they feed, the bugs are bloated and sluggish, and must jettison the waste so they can make their escape.
Here’s how it happens: when the kissing bug finds a snoozing victim and feeds, its levels of serotonin and diuretic hormones rise sharply, targeting the insect’s midgut and Malpighian tubules (the equivalent of kidneys), and triggering the release of waste. About four hours later, a peptide named CAP2b is released in the insect’s gut, abolishing the effect of the diuretic hormones.
Paluzzi has identified two genes (RhoprCAPA-alpha and RhoprCAPA-beta) that carry the chemical recipe for the peptides that stop diuresis. With that information, he hopes to create a peptide “agonist”-something that would enhance the activity of the CAP2B peptide and prevent the insect from leaving waste (and the parasite) on the wound. In theory, says Paluzzi, this might be an insecticide-like room spray or topical lotion that is biologically stable and has no effect on humans or other insects. Paluzzi is collaborating with a structural biochemist at the U.S. Food and Drug Administration in Texas, with the ultimate goal of creating a pest control solution, but he cautions that a market-ready product is many years away.
The research was funded by the Natural Sciences and Engineering Research Council of Canada, through a discovery grant to Professor Ian Orchard of the Department of Biology and a Canada Graduate Scholarship to Paluzzi.
Sourced and published by Henry Sapiecha 2nd May 2010
ScienceDaily (Apr. 29, 2010) — Like all vertebrates, snakes, mice and humans have in common a skeleton made of segments, the vertebrae. But a snake has between 200-400 ribs extending from all vertebrae, from the neck to the tail-end, whereas mice have only 13 pairs of ribs, and humans have 12 pairs, in both cases making up the ribcage.
In the latest issue of Developmental Cell, researchers from the Instituto Gulbenkian de Ciência, in Portugal, reveal that, contrary to what was thought, making ribs is not the default state for vertebrates, but is actually an active process of balancing the activities of a remarkable class of genes — the Hox genes.
It was thought that the rib less region of the mouse embryo was the result of a rib-inhibiting programme, driven by Hox10 genes. Indeed, previous studies, in which Hox10 genes were inactivated in the embryo, generated mice with extra ribs. However, by forcing another class of Hox genes (Hox6) to be activated in future rib-less regions of the mouse embryo, Moises Mallo and his team bred mice that also have extra ribs, both in the neck area, and from just after the rib cage, all the way down to the tail, resembling a snake-like skeleton.
“It was an extraordinary, and clear-cut result,” says Mallo, “suggesting that these two groups of Hox genes balance each other out: one actively promotes rib formation to produce the thoracic region, while the other blocks this activity in the lumbar region. Our results have unveiled this balance.”
The researchers went on to unpick the genes involved in this process, and came up with yet another surprising finding: that the whole process relies on first hitting so-called muscle genes in the embryo, which then provide signals to switch on the ‘rib’ genes to make both ribs and muscle, in a coordinated process.
According to Mallo, “Our findings reveal a more complicated process than we would have imagined, but one that makes perfect sense, from a functional and evolutionary point of view: it is no good to make ribs without muscle, so, in the embryo, the production of both ribs and their associated muscles is under the control of a single and coordinated mechanism.”
Sourced and published by Henry Sapiecha 29th April 2010
ScienceDaily (Nov. 28, 2007) — A diet high in refined carbohydrates, like white rice or white bread, is associated with increased prostate tumor growth in mice.
Having too much insulin in the blood, a condition called hyperinsulinemia, is associated with poorer outcomes in patients with prostate cancer. Vasundara Venkateswaran, Ph.D., of Sunnybrook Health Sciences Centre in Toronto and colleagues investigated whether high insulin levels caused by eating a diet high in refined carbohydrates would lead to more rapid growth of prostate tumors in mice.
Forty mice were randomly assigned to either a high carbohydrate-high fat diet or a low carbohydrate-high fat one for nine weeks. The researchers measured the animals’ weight, tumor size, and insulin levels weekly. Mice on the high carbohydrate diet gained more weight, had faster growing tumors, and had higher insulin levels than mice on the low carbohydrate diet.
“Our results provide support for the concept that diets associated with a reduction in insulin level may have benefits for prostate cancer patients, particularly for the subset of patients who are hyperinsulinemic,” the authors write.
Sourced and published by Henry Sapiecha 19th April 2010
