Spinal cord stimulator offers new hope against Parkinson's

Spinal cord stimulator offers new hope against Parkinson's

A simple small electric stimulator of the spinal cord brings new hope to treat the symptoms of Parkinson's disease, according to promising research carried out on mice in the United States.

This stimulator was attached to the top of the spine of mice and rats whose researchers had significantly reduced the body's dopamine content to replicate the biological characteristics of people with Parkinson's at different stages of this neurodegeneration. progressive incurable.

Dopamine is a small molecule that provides communication between neurons, nerve cells in the brain.

When the pacemaker was started, the dopamine-free animals whose movements were slow and stiff began to move quite normally.

This improvement was generally observed 3.35 seconds after the start of the stimulation.

"We observed almost immediately a dramatic change in the animals' ability to move when the device electrically stimulated their spinal cord," says Dr. Miguel Nicolelis, a neurologist at the Duke University School of Medicine in North Carolina. (Southeast), one of the authors of this study published in the journal Science dated March 20.

"In addition, this stimulator is simple to use and much less invasive than current approaches such as drugs or deep electrical stimulation of the brain," adds the researcher.

"Finally this stimulator could be used very widely with the most commonly prescribed drugs to treat Parkinson's," notes Dr. Nicolelis.

When the spinal cord stimulator was used on these rodents without drugs they were 26 times more active than other non-stimulated mice and rats.

Animals whose spinal cord was electrically stimulated also receiving two doses of the L-DOPA anti-Parkinsonian drug had movements comparable to five doses of this treatment in other animals without electrical stimulation.

L-DOPA, which increases the amount of dopamine in the brain, is one of the most commonly used drugs to reduce Parkinson's symptoms.

"This research addresses an important need because L-DOPA eventually loses its effects with the worsening of Parkinson's symptoms," says Romulo Fuentes of Duke University and the lead author of this study.

In addition, deep brain electrical stimulation only applies to a limited number of patients, says the researcher.

In a healthy person, neurons light up at different frequencies, reacting to information transmitted by the brain to initiate normal body movements, a process compromised in someone with Parkinson's.

"This stimulator of the spinal cord acts as an interface between the brain and the neural system to facilitate the transmission of nerve impulses", notes Per Petersson, one of the authors of the study.

"If we can show that this stimulator is safe and effective in primates and humans, almost all Parkinson's patients will soon be able to use it," says Dr. Nicolelis.

More than 50,000 Americans have Parkinson's and 50,000 new cases are diagnosed annually.

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Curcumin could help fight against Alzheimer's disease

Curcumin could help fight against Alzheimer's disease

Vitamin D and curcumin, a chemical element found in turmeric, may prove useful in preventing and treating Alzheimer's disease, according to a study published in the July edition of the Journal of Alzheimer's Disease.

A team of researchers from the University of California at Los Angeles (UCLA) and the University of California at Riverside have discovered that the combination of the two substances stimulates the immune system against the spread of amyloid plaques in the brain, which is thought to that they cause dementia in Alzheimer's patients. "We hope that vitamin D3 and curcumin, two nutrients found in nature, offer new opportunities for the prevention and treatment of Alzheimer's disease," he said. Dr. Milan Fiala, lead author of the study and researcher at David Geffen School of Medicine at UCLA.

Synthetic curcumin has been found to be more effective than natural curcumin, because it is absorbed more quickly, and breaks down more slowly than natural curcumin, says the study.

Many studies show that supplemental curcumin (a turmeric-based diet does not provide enough of the substance) is anti-oxidant and anti-inflammatory, and could reduce the production of amyloid plaques.

Vitamin D3, a form of vitamin D, is well known for its beneficial role on the bones and the immune system. It comes mainly from the sun, and is synthesized through the skin.

"Since vitamin D and curcumin work differently with the immune system, we may discover that a combination of the two, or each taken separately, may be more effective, depending on the patient," said Milan Fiala, stating moreover more research needs to be done before any dosage can be advocated.

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Stem cells to make teeth grow back.

Stem cells to push teeth back

In the adult, it is possible to do to grow new perfectly functional teeth from a set of stem cells. This is what a Japanese team has just demonstrated ... on mice. But hope is good to one day adapt this feat to the human being.

The recipe for growing teeth seems simple in principle. Takashi Tsuji and his team of stem cell biology from the Tokyo Science Faculty have just detailed it in the Pnas, American scientific journal. The principle is to cultivate stem cells, an idea that is not new and that has raised hopes and experiments for several years. But the Japanese team, it has succeeded to the end ...

The biologists first took tissues at the origin of the teeth from a very young mouse embryo and isolated two types of cells, epithelial (forming the epithelia, that is to say the skin) and mesenchymal cells, primarily cartilage, bone and connective tissue.

These two cell populations were then fused to obtain a sort of germ, cultured for 5-7 days. The biologists then implanted it in the upper jaw of an adult mouse in place of a tooth that had previously been removed.

After 36 days, the new teeth had pierced the gingiva and, after 49 days, had reached normal size and, well aligned with the teeth of the lower jaw, allowed perfect chewing.

Indiscernible from the original teeth

Upon observation, these new teeth appeared quite normal, with internal innervation, roots and enamel protection. Ligaments have formed, connecting these teeth to the underlying bones and sensory nerves, as in the naturally grown dentition. The new teeth therefore provide a sensitivity to pressure, which is of course impossible with a prosthesis or an implant. In short, the teeth thus generated have, say the researchers, all the characteristics of their counterparts appeared normally.

According to Japanese authors, this technique could very well be applied in humans. The germ would then be made from stem cells taken from the person, since it is now known that such cells, including mesenchymal cells, are not reserved for embryos. It exists in adults in the bone marrow.

The scientific success is very interesting, but, however, if the operation is actually possible in humans, what remains to prove, the technique is still far from the dentists ...

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The saliva of a tick, hope of Brazilian researchers to cure cancer.

The saliva of a tick, hope of Brazilian researchers to cure cancer

The tick does not transmit not only infectious diseases: its saliva also contains a protein that could cure cancers of the skin, liver and pancreas, according to Brazilian researchers.

By studying a South American specimen of this blood-sucking parasite, Amblyomma cajennense, they discovered that this Photoprotein destroys cancer cells while sparing healthy cells.

"This is a major breakthrough," says Ana Marisa Chudzinski-Tavassi, a researcher in molecular biology at the Butantan Institute in Sao Paulo.

"The substance contained in the saliva of this tick ... could be the cure for cancer," she told AFP.

The researcher says she accidentally discovered the virtues of this protein, called Active Factor X, by testing the anti-coagulant properties of tick saliva, which allow the parasite to gorse itself on the blood of animals or humans to which it is attached. 'attack.

The protein has common characteristics with a widespread anti-coagulant called TFPI, or Kunitz inhibitor, which also acts on cell growth.

Lab tests were then conducted to see if the protein produced effects on the cancer cells and their results exceeded all researchers' expectations.

"To our surprise, she did not kill the healthy cells, which were also tested," says Ms. Chudzinski-Tavassi. "But she killed the cancer cells that were analyzed."

In her modest laboratory of the institute, with decrepit walls, the researcher collects saliva from ticks by placing straws under their heads.

The few drops thus collected are then reproduced in yeast tanks to carry out tests on cancer laboratory rats.

The results are more than promising.

"If I treat a small tumor of an animal daily for 14 days, this tumor does not develop and even, it decreases. The mass of the tumor decreases. And if you treat it for 42 days, the tumor disappears completely, "says the researcher.

To produce a drug, however, will require years of clinical testing and large investments, two things that Brazil can not provide at the moment.

"To make a discovery is one thing. Turning it into a drug is another totally different, "says Chudzinski-Tavassi.

In the meantime, she has filed a patent application for the protein of this tick and travels the world to present his discovery, which has also been the subject of publications in medical journals.

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Gene therapy has made color vision to monkeys.

Gene therapy has made color vision to monkeys.

Gene therapy has made color vision to monkeys

Two squirrel monkeys, who could only distinguish yellow and blue, acquired a complete perception of colors through the insertion of a human gene in their retina. This discovery, which is surprising, suggests possible treatments for diseases of vision, even congenital.

Sam and Dalton are two squirrel monkeys, also called sairmi (Saimiri sciureus), hence the name of the first. Two years ago, like all males of their species, they could only distinguish two shades, yellow and blue, but neither red nor green. Hence the name of the second, which is that of John Dalton, the English physician who described in 1798 this hereditary disorder of the vision called since color blindness. Today, Sam and Dalton triumph over all the tests imagined to detect this disease, as evidenced by a publication in the journal Nature.

For the past ten years, these two monkeys have been living with Maureen and Jay Neitz, a couple of ophthalmologists working at the University of Washington ("they're like our kids," they say). Sam and Dalton were extensively trained in color vision screening tests, judging by the video shot by the team.

Meanwhile, William Hauswirth's team (University of Florida) was developing a method of gene therapy to slide a gene into some cells of the retina, the cones, responsible for color vision. In male squirrels, there are no cones perceiving green and red. They are dichromates (like cats of both sexes), while females - and non-colorblind humans - are trichromatic.

The brain has also found the colors

Two years ago, these two monkeys underwent an intervention to receive genes, of human origin, conveyed into the cones by a harmless adenovirus. These genes are used to make a protein of the opsin family, these light-sensitive pigments that function within a molecular complex called rhodopsin.

After the success of this intervention, the question was twofold. Will the cones thus treated develop a real sensitivity to colors? And, above all, will the brains of Sam and Dalton, who have never seen either red or green, know how to analyze these completely new signals?

According to Maureen and Jay Neitz, who live continuously with both animals, the first effects appeared after only five weeks. Twenty weeks after the intervention, Sam and Dalton began to point, during tests, the red and green areas displayed on the screen. Jay Neitz says he himself was surprised.

The team then continued testing for a year and a half to ensure performance and progress. Today, Sam and Dalton visualize the colors as well or almost as the females of the species. Moreover, after two years, no side effects were noted.

A therapeutic hope

"The addition of a third opsine in an adult who does not see either green or red leads to the normal behavior of a trichromatic vision," the authors conclude in the journal Nature. According to Jay Neitz, experience shows that even in these monkeys that do not recognize all the colors, the neural circuits capable of analyzing them are present in the brain. It can also be interpreted as a great plasticity of the central nervous system.

On the medical level, this result is of great interest. This is not the first time that gene therapy improves vision. Success has already been achieved in dogs and humans in the case of Leber's congenital amaurosis.

It shows that it is possible to treat sight disorders, even when the origin is congenital, which was not self-evident. Moreover, as the authors point out, the DNA used for the repair was human, which is one less problem for the transfer of this technique to humans.

Particularly targeted are vision disorders involving cones, such as color blindness but also loss of central vision, such as macular degeneration, due to age or diseases, including diabetes.

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Towards an anti-cocaine vaccine.

Towards an anti-cocaine vaccine

Cocaine addiction could be countered by a simple vaccine?

US researchers say the vaccine they have created is causing cocaine addicts to abandon their drug use. In fact, the injected substance increases the level of antibodies against the drug, which makes it inactive before it reaches the brain and produces its euphoric effects.

Teams from Yale University and Baylor College come to this conclusion after six months of clinical trial.

The results show that 38% of vaccinated cocaine addicts produce a sufficient level of antibodies to block the effects of the drug. As a result, cocaine use has plummeted, with some consumers ceasing to take any.

A downside however: the effects have not persisted for more than two months.

The authors therefore believe that optimal treatment would require repeated vaccinations to maintain adequate antibody levels.

The lead author of the study, Thomas Kosten, has been developing a cocaine vaccine for 15 years.

"Fifteen years ago, everyone said that it was impossible to produce antibodies against small molecules like this one. Dr. Thomas Kosten

According to the International Narcotics Control Board, cocaine is the second most commonly used drug in North America, accounting for 2.3 million users in the United States alone.

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Risks of the cell phones: a rather reassuring study.

Risks of the cell phones on brain cancer: a rather reassuring study

The number of brain cancers in four Nordic countries has not increased with the arrival of the mobile.

While the battle is in full swing on the possible risks of relay antennas, contested by many scientists, but put forward by some associations, the debate on the dangers of the mobile phone, muted, risks being revived with the Expected publication for the end of the year of the large international study Interphone conducted under the aegis of 37 scientists in 13 countries.

In the meantime, another smaller survey has been published in the Journal of the National Cancer Institute, analyzing the evolution of brain tumors between 1974 and 2003 in Denmark, Finland, Norway and Norway. Sweden. The aim is to check whether the introduction of the mobile phone in the early 1990s was accompanied by an increase in brain tumors. Clearly examine the evolution curves of the number of brain cancers to see if there was a "break" coinciding with the appearance of mobile.

Several factors

The results are rather reassuring. Using cancer registries from these four countries, the researchers looked at 59,984 men and women aged 20 to 79 who had glioma or meningioma, the two major brain tumors, during thirty years of surveillance. The results show that between 1974 and 2003, the number of new cases of glioma increased by 0.5% per year in men and by 0.2% in women. For meningioma, growth was 0.8% for men and 3.8% for women in the early 1990s. This steady increase is due to several factors. In the mid-1970s, the advent of scanners revolutionized the diagnosis of brain tumors, as did the arrival in the mid-1980s of nuclear magnetic resonance imaging. In addition, the increase in life expectancy in all Western European countries has contributed to the rise in the number of all cancers.

The authors conclude: "We did not detect any clear change in the number of brain cancers between 1998 and 2003. This number was either stable in some age groups, slightly decreasing in others, or continuing to decline. increase, with an increase that began well before the introduction of mobile. We did not find an increase in brain cancers related to mobile phones. "

The preliminary results of Interphone go in the same direction, with a gray area for heavy users. The authors believe that a risk can not be totally eliminated, either because it is too weak to be detected with the current epidemiological tools, or because the decline is insufficient. Finally, this study did not examine the case of children, major users of laptops for which the greatest caution is recommended.

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Artificial oxygen carriers.

Artificial oxygen carriers

American researchers have developed synthetic particles that closely mimic the key features and functions of the globules natural red, mainly the ability to carry oxygen.

One of the solutions to deal with the decline in blood donations is the production of artificial blood capable of performing the same functions as the fluid circulating in our veins. A goal not so simple to achieve because blood cells have very special characteristics. Starting with red blood cells, or red blood cells, which provide in the body the transport of oxygen from the lungs to different organs and tissues.

The progress made in the field of biomaterials and nanoparticles, however, give hope for progress in the coming years. An important first step seems to have been taken by researchers at the University of Santa Barbara, in collaboration with scientists from the University of Michigan.

They synthesized particles that mimic the structural and functional characteristics of red blood cells. Similar to their natural counterparts, Synthetic Blood Red Cells (sBRCs) have the ability to carry oxygen through vessels, capillaries, smaller than their own diameter.

In addition, they can also carry drugs or contrast molecules to perform radiological examinations. And the technique used by researchers has other potentialities. In their article, published online at the PNAS website, they discuss the possibility of developing particles that mimic the shape and properties of diseased cells such as deformed red blood cells found in sickle cell anemia.

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Disinfectants make bacteria resistant.

Disinfectants make bacteria resistant

Researchers at the University of Galway have discovered that disinfectants tend to increase antibiotic resistance.

The researchers were interested in the bacterium Pseudomonas aeruginosa or pyocyanic bacillus. It is responsible for many nosocomial infections and appears highly resistant to antiseptic products. It causes a lot of infections all over the body. The bacteria has been put in front of a series of disinfectant products, used in hospitals and homes. The researchers found that it resisted these products but also antibiotics.

Disinfecting products would indeed promote the emergence of bacteria even more resistant to antibiotics.For Dr. Fleming, head of the study, this discovery is very worrying because the bacteria are resistant to antibiotics without having been put in contact with them. He now wants to expand his field of research to other types of disinfectants, to understand the process of natural resistance developed by bacteria.

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Mice rescued from Alzheimer's by mobile phone?

Mice rescued from Alzheimer's by mobile phone?

Used for mobile telephony, radio frequency waves would they have beneficial effects on Alzheimer's disease?

Surprising as it may seem, the question is raised by a study conducted on mice by a team of researchers from the University of South Florida (USA), the Medical University of Saitama (Japan) and from Dalian Medical University (China). The work of these scientists, who claim to have no conflict of interest with the telephone industry, is published Wednesday, January 6 in the Journal of Alzheimer's Disease.

"This article reports the first evidence that long-term exposure to an electromagnetic field (EMF) directly associated with the use of a mobile phone (918 MHz, 0.25 W / kg) results in cognitive benefit," write Gary Arendash and his colleagues. The researchers indicate that protective cognitive effects and cognitive performance enhancing effects have been found in both normal and genetically engineered mice to develop Alzheimer-type abnormalities.

In practice, 96 mice, divided into four groups, were used. Exposure of twice an hour per day to RF waves was standardized and lasted seven to nine months: animal cages contained a central antenna generating a mobile signal.

When submitted to the CEM when they were young adults, before the appearance of Alzheimer's symptoms, the transgenic mice did not have any alteration of their cognitive abilities. When the exposure occurred at a later age, when the symptoms of the disease had appeared, the impairments of the memory, evaluated by tests, disappeared. More surprisingly, normal mice showed an improvement in their memory performance.

To explain the results that they themselves describe as surprising, the authors mention several possible mechanisms, which may complement each other: suppression of aggregation of amyloid plaques, a key phenomenon in the setting up of Alzheimer's disease; increased activity of neurons, but also temperature increase of 1 degree in the brain of exposed mice.

Studies have already indicated improvements in memory performance, and some therapies rely on EMFs, but it is premature to draw definitive conclusions. "We need to be cautious in extrapolating our results to mobile phone use and exposure to EMF in humans," warn the authors.