Normally, when bone gets damaged, because it is partly made of living cells, it can heal itself by growing new tissue or remodeling. But while teeth are bone-like, they do not have this facility. So how do they survive a lifetime of wear and tear?
In the journal Nano Letters, researchers led by members from the Charité Universitätsmedizin Berlin in Germany describe how they examined the mechanical properties of tiny nanoparticle and fiber structures inside dentin - the layer of softer, porous material that lies under the much harder enamel covering of teeth.
The researchers already knew that dentin contains tiny layered structures of mineral nanoparticles embedded in, and firmly attached to, collagen protein fibers.
And while it was thought these layers of mineral nanoparticles and collagen proteins make teeth tough and damage resistant - it was not clear how they stopped cracks from growing.
Mineral nanoparticles in collagen structures in dentin are 'pre-compressed'
The new study reveals that the nanoparticles are "pre-compressed" and it is this that stops cracks from traveling, as senior author Dr. Paul Zaslansky of the Julius Wolff Institute of the Charité explains:
"The compressed state helps to prevent cracks from developing and we found that compression takes place in such a way that cracks cannot easily reach the tooth inner parts, which might damage the sensitive pulp."
Engineers use compression to strengthen industrial materials for stress-bearing jobs such as gears and turbine blades. Now this study reveals that evolution may have arrived at this solution in teeth long before industrial man.
The researchers examined the tiny structures of tooth dentin using micro- and nanofocused X-ray beams generated by advanced synchrotron-based diffraction equipment, some of which is based at the European Synchrotron Radiation Facility in Grenoble, France.
They altered the humidity of dentin samples to change its mechanical properties and study how stress was generated in the material.
They found that when the collagen fibers shrank, this increased the compression in the attached mineral nanoparticles.
In further tests, they found that heat weakens the link between the nanoparticles and the fibers, making the dentin more brittle.
Study may lead to tougher ceramic materials for tooth replacements
First author Jean-Baptiste Forien, a PhD student in the Julius Wolff Institute, says:
"We therefore believe that the balance of stresses between the particles and the protein is important for the extended survival of teeth in the mouth."
The team suggests their findings may explain why artificial tooth replacements are not as resilient as healthy, natural teeth. Perhaps ceramic materials are too "passive" and do not respond to stress in the same way as the natural, pre-compressed structures.

Source= http://www.medicalnewstoday.com/articles/295501.php

Dentin· MEDICAL DISEASES· MEDICAL NEWS· Medical News Today· Nanostructure· Scientists· Show How· Stops· Teeth Cracking

Scientists Show How Nanostructure Of Dentin Stops Teeth Cracking:

During vaginal birth, microbiota that populate the mother's vagina are passed on to the baby. This microbiota aid normal colonization of the child's gut, helping immune system and metabolism development.
According to the researchers, including study co-author Tracy Bale, PhD, of the University of Pennsylvania, since vaginal microbiota influences offspring's gut colonization during an important stage of brain development, it is believed such microbiota also influences brain development.
For their study, Bale and colleagues set out to assess how stress during pregnancy may affect the population of microbes within a mother's vagina, and how this may influence the gut microbiome and brain development of offspring.
They did so by exposing pregnant mice to stress triggers during early pregnancy, such as new noises, predator odors and restraint.
The researchers collected tissue from the vaginal lavages of the mice 2 days after they gave birth, in order to assess their vaginal microbiome.
The team investigated the gut microbiome of the mouse pups by analyzing their feces, and they also analyzed the transportation of amino acids from the gut of the pups to their brain.
Findings highlight the important role of the vaginal microbiome in offspring development
The researchers found that mice exposed to stress during early pregnancy experienced alterations in their vaginal microbiome, which disrupted the gut microbiota composition of their offspring.
The team found that male offspring was particularly prone to gut microbiome disruption as a result of changes to a mother's vaginal microbiome.
"Mom's stress during pregnancy can impact her offspring's development, including the brain, through changes in the vaginal microbiome that are passed on during vaginal birth," explains Bale.
"As the neonate's gut is initially populated by the maternal vaginal microbiome," she adds, "changes produced by maternal stress can alter this initial microbe population as well as determine many aspects of the host's immune system that are also established during this early period."
The team says their findings emphasize the importance of a mother's vaginal microbiome for populating the gut microbiome of offspring during childbirth, highlighting the negative effects maternal stress may have on this crucial process.

Source= http://www.medicalnewstoday.com/articles/295448.php

'Alters· Development· During· Influencing· MEDICAL NEWS· Medical News Today· Microbiota· Offspring· Stress During Pregnancy· Vaginal· Vaginal Birth

Stress During Pregnancy 'Alters Vaginal Microbiome, Influencing Offspring Development:'

The Food and Drug Administration (FDA) say they have finally determined that partially hydrogenated oils (PHOs) - a major source of artificial trans fat in the American diet - are not "generally recognized as safe" for human consumption.

The regulators are giving food manufacturers 3 years - until 18th June, 2018 - to remove PHOs from food products.

This gives companies time to reformulate products so they do not contain PHOs, or to ask the FDA for permission to use them.

"Following the compliance period, no PHOs can be added to human food unless they are otherwise approved by the FDA," say the regulators.

FDA's Acting Commissioner Dr. Stephen Ostroff says the "action is expected to reduce coronary heart disease and prevent thousands of fatal heart attacks every year."

The FDA announced a preliminary determination to regard PHOs as unsafe to eat in 2013. That followed a review of the scientific evidence and consultation with experts.

The regulators are now finalizing the determination after considering comments from the public.

Director of the FDA's Food Safety and Applied Nutrition Center Dr. Susan Mayne says:

"This determination is based on extensive research into the effects of PHOs, as well as input from all stakeholders received during the public comment period."

While consumption has fallen, 'it is still a public health concern'

Food companies use artificial trans fats to improve the texture, extend the shelf life and increase the stability of processed foods. They are cheaper and more readily available than natural versions from meat and dairy sources.

Since 2006, companies have had to show trans fat content on the nutrition facts labels of food products sold in the US.

The FDA say that while trans fat consumption by Americans has fallen by 78% between 2003 and 2012, the current level of consumption remains a public health concern.

Companies are already removing PHOs from processed foods, and the FDA anticipate that many will achieve compliance before the deadline.

According to the Centers for Disease Control and Prevention (CDC), the main sources of PHOs in the American diet are cakes, cookies, pies, margarines and spreads, fried foods, savory snacks such as microwave popcorn, frozen pizza, ready-to-use frosting and coffee creamers.

Why are PHOs bad for health?

PHOs are made by heating up a food oil such as soybean or cottonseed in the presence of hydrogen and a catalyst. This makes the oil into a semi-solid, partially saturated fatty acid - like margarine - making it easier to use as a shortening in baked goods.

Trans fats are so called because when hydrogenation breaks double bonds between carbon atoms in the long-chain fatty acid molecules, this results in the hydrogen atoms attached to the carbon atoms at a double bond being on opposite sides of the double bond ("trans" means "other side," or "across").

This "trans" configuration is different to naturally occurring versions, which have a "cis" configuration, where the hydrogen atoms attached to carbon at double bonds are on the same side of the double bond.

The trans configuration in the fatty acid molecules of manufactured PHOs is thought to be what makes them bad for health - consuming them lowers "good" cholesterol (high-density lipoprotein, or HDL) and increases "bad" cholesterol (low-density lipoprotein, or LDL) in the body, raising the risk of coronary heart disease.

The CDC say eliminating the use of PHOs in food could prevent 10,000-20,000 heart attacks and 3,000-7,000 coronary heart disease deaths each year in the US.

In November 2014, MNT reported a study of hundreds of healthy working-age men that found higher consumption of trans fats was linked to poorer memory. Speculating on the reason behind the link, the researchers suggested trans fats increase oxidative stress, which affects cell energy.

Source= http://www.medicalnewstoday.com/articles/295483.php

Coffee· cookies· Food· Health News· Heart Disease· MEDICAL NEWS· Medical News Today· Nutrition

FDA: No More Unsafe' Trans Fats:

The flavonoid antioxidants in dark chocolate have long been hailed for their supposed beneficial effect in protecting against certain conditions. One study published last year suggested eating chocolate could prevent obesity and diabetes.

And another suggested eating dark chocolate in moderation could be good for the heart.

Though dark chocolate has previously been identified as having protective properties against cardiovascular disease, until now, there have not been any large-scale intervention studies to assess the potential benefits of dark and milk chocolate.

Findings from the latest research - which also investigates potential health benefits of milk chocolate - come from the EPIC-Norfolk study, which follows men and women in Norfolk, England, using food frequency and lifestyle questionnaires. The results are published in the journal Heart.

In addition to the EPIC study, the team also conducted a systematic review of all available published evidence on links between chocolate and cardiovascular disease (CVD), which involves almost 158,000 people internationally.

Study participants were followed for an average of nearly 12 years, and during this time, 14% of them experienced either astroke or coronary heart disease.

Higher chocolate intake linked to more health benefits

Of the study participants, 20% said they did not eat any chocolate, while the others had an average daily consumption of 7 g. Some even ate up to 100 g each day.

The researchers found that people who ate higher levels of chocolate typically had a younger age; lower weight, waist-to-hip ratio, systolic blood pressure and inflammatory proteins; less incidence of diabetes and more physical activity. All of these add up to a "favorable" CVD risk profile.

Additionally, eating more chocolate was linked with higher energy intake and a diet that consisted of more fat and carbs, and less protein and alcohol.

Importantly, compared with those who did not eat any chocolate, the people who ate more chocolate had an 11% lower risk of CVD and a 25% lower risk of associated death. They also had a 9% lower risk of hospital admission or death resulting from coronary heart disease and a 23% lower risk of stroke.

Results also showed that among those whose inflammatory protein level was measured, those who ate the most chocolate had an 18% lower risk than those who ate the least.

The systematic review likewise found a significantly lower risk of both stroke and CVD in people who regularly ate chocolate, and there was also a 25% lower risk of any episode of CVD and a 45% lower risk of associated death.

Health benefits from milk chocolate, too

Though the results are significant and the sample size is very large, there are certain limitations to this study, the researchers say. Because this was an observational study, they cannot draw conclusions about cause and effect.

Food frequency questionnaires - which were used in the study - always involve recall bias and underestimation of what was eaten, particularly among women and obese participants. Their results could also be explained by reverse causation, specifically where those with a higher CVD risk eat less chocolate than those who are healthier.

The researchers still conclude that their "evidence suggests that higher chocolate intake is associated with a lower risk of future cardiovascular events."

Plus, individuals who prefer milk chocolate over dark chocolate can also feel good about the study's results, as the EPIC-Norfolk participants ate milk chocolate more often than dark chocolate, which suggests beneficial effects may arise from eating this type of chocolate.

Chocolate· Consumption· Heart Disease Risk· Linked to· Lower Stroke· MEDICAL NEWS· Medical News Today

Chocolate Consumption Linked to Lower Stroke and Heart Disease Risk:

The analysis, published in JAMA Internal Medicine, was written by Rebecca Siegel of the American Cancer Society in Atlanta, GA, and coauthors.

The new data are relevant, they say, because estimates are out of date since the 2014 US Surgeon General's report, which covered "cancer overall and lung cancer specifically but not separately for the 11 other cancers found to be caused by smoking."

Further, smoking patterns have changed. For example, while the level of smoking fell from 23.2% in 2000 to 18.1% in 2012, the authors cite evidence to suggest the risk of cancer death among smokers can rise over time.

The data used by the authors came from results of the 2011 National Health Interview Survey, the Cancer Prevention Study II, and a study known as the pooled contemporary cohort by Thun and coauthors.

The analysis estimates that 167,805 deaths - out of a total of 345,962 from the 12 cancers - were attributable to smoking cigarettes.

Other results of the research include:

• Respiratory cancers - of the lung, bronchus and trachea - attributed for most smoking-related deaths (125,799)
• Voice box cancers related to smoking accounted for 2,856 deaths, which were 76.6% of all larynx cases
• About half of the deaths from cancers of the oral cavity, esophagus and urinary bladder were attributable to smoking.

The study's estimates may not be fully representative because its populations were less racially diverse and more educated than the American population at large, and the analysis excluded tobacco exposure from sources other than cigarettes, including from second-hand smoke.

The new study has included two cancers previously left out of estimates because of their more recent links to smoking - colorectal and liver cancers.

Cancers· Estimate Shows· MEDICAL NEWS· Medical News Today· Smoking Causes

Smoking Causes Half of All Deaths from 12 Cancers, Estimate Shows:

The Brio Neurostimulation System is the second device to be approved by the US Food and Drug Administration (FDA) for treating these disorders and can reduce symptoms such as balance problems, tremors and walking difficulties.

"There are no cures for Parkinson's disease or essential tremor, but finding better ways to manage symptoms is essential for patients," says Dr. William Maisel of the FDA. "This new device adds to the array of treatment options to help people living with Parkinson's and essential tremor enjoy better, more productive lives."

Around one million people in the US are believed to have Parkinson's disease, with an estimated 50,000 people newly diagnosed with the progressive nervous system disorder each year.

Parkinson's disease symptoms are caused by the degeneration of nerve cells that produce the neurotransmitter dopamine, a chemical that helps transmit messages from the brain related to the control and coordination of body movements.

The cause of essential tremor is currently unknown, but the condition leads to involuntary shaking - typically in the hands - that is similar to that caused by Parkinson's disease. The condition affects several million people in the US, mostly over the age of 40.

Drugs are frequently used to reduce tremors in people with Parkinson's disease and essential tremor, but sometimes medicine is unable to adequately alleviate disruptive symptoms. When this is the case, the new Brio Neurostimulation System could be of use.

A battery-powered generator that sends electrical pulses to the brain

Manufactured by St. Jude Medical in St. Paul, MN, the device consists of a small electrical pulse generator implanted under the skin of the upper chest. The generator is connected to electrodes positioned within the brain according to whether the device is being used to treat Parkinson's disease or essential tremor.

The battery-powered pulse generator is fully rechargeable and delivers low-intensity electrical pulses to these electrodes through wires. Health care providers can adjust the activity of the pulse generator in order to maximize the effects for the patients using the device.

Among the data presented to the FDA to demonstrate the safety and efficacy of the device were two clinical studies: one involving 136 participants with Parkinson's disease and one involving 127 patients with essential tremor.

In both studies, the participants were experiencing tremors that were not being adequately relieved by medication. After 3 months for the patient with Parkinson's disease and 6 months for the patients with essential tremor, the researchers assessed the effectiveness of the device.

For both groups of patients, significant improvement in symptoms was noted when the device was turned on compared with when the device was turned off. In the patients with Parkinson's disease, the device was used alongside medication while the majority of patients with essential tremor could manage their symptoms without additional drug therapy.

A number of adverse events related to use of the device were observed by researchers. These ranged from infection and dislocation of the device under the skin to more severe events such as intracranial bleeding. These events occurred infrequently enough, however, for the FDA approve the device.

Earlier this year, Medical News Today reported on a study finding that difficult Parkinson's symptoms such as swallowing dysfunction and freezing of gait respond were improved more with low-frequency deep brain stimulation compared with the more usual high-frequency brain stimulation.

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Brain Implant· Brio Neurostimulation· MEDICAL NEWS· Medical News Today· Treating Symptoms

FDA Approve Brain Implant for Treating Symptoms of Parkinson's: