UC Science Today

If you often snack throughout the day, your teeth are at risk. That’s according to Peter Rechmann, a professor of dentistry at the University of California, San Francisco. In his recent study called Caries Management by Risk Assessment, Rechmann has shed light on how to save your teeth before caries ruins them. So for those who like to graze during the day, Rechman says one tip to prevent cavities is to eat fast.

“We kept on telling our patients - you can have chocolate, no problem, eat the whole thing in 10 minutes and brush your teeth or use chewing gums, but don’t eat the chocolate over, piece by piece, every 10 minutes a piece. That is terrible.”

Savoring like this leaves more sugar for bacteria in your mouth. And types of snack also matter for your dental hygiene. So, try cutting down on carbohydrates.

“I even suggest not to snack at all on carbohydrates. So if you do more than three times, your caries risk really, really goes up.”

Over the years, cancer treatment has improved with minimally-invasive surgeries and more localized chemotherapy techniques. But even if chemotherapy can be localized and delivered directly to a tumor, over half of the drug can pass the tumor and become systemic.

"It goes all over your body. The current popular drugs, they are effective, but they are also very toxic. So, they have bad side effects."

That’s materials scientist Chelsea Chen of the Lawrence Berkeley National Laboratory. She collaborated with a University of California, San Francisco physician to come up with a device that can filter out the toxins.

"What he came up with is that he wants to place this device at the draining vein exiting the tumor, so this device can catch the excessive chemotherapy before it enters the body circulation and this way, it further reduces the systemic toxicity of the drugs. So we designed this device that we call the ‘ChemoFilter’."

Chen says it may be ready for treatment in a few years.

There’s new insight into how race and ethnicity affect health, thanks to new research at the University of California, San Francisco. Study leader Noah Zaitlen explains the connection.

"People from different countries, from different communities get sick from different diseases, they respond differently to different medications. We know that some of that is because of differences in their genetics and some of that is because of differences in their environment."

This includes exposure to pollution, differences in diet or stress levels, all of which scientists and doctors overlooked in the past in favor of genetics and ancestry. And this approach, Zaitlen says, has shaped the way patients get screened.

"When you walk into a hospital right now, you fill out this form, you see two choices for ethnicity – it can be Hispanic or non-Hispanic and then you have these racial categories and the selection can impact how you are treated. Diagnostic tests will get reported differently depending on which category you check."

To better assess patients’ health, Zaitlen suggests that doctors include social and environmental factors, too.

If a brain functions normally, neuron excitation and inhibition work in balance.

“And when you have this good balance, then you have normal cognitive function. When this is disrupted, that’s when people have seizures – where you have excess excitation, dysregulated activity of the brain, and don’t have appropriate inhibition.”

That’s neurologist Mercedes Paredes of the University of California, San Francisco. She says researchers used to pay more attention to excitatory neurons in their studies and downplayed the role of inhibitory neurons. But according to Paredes these neurons are crucial for the newborns’ brain development.

“So excitatory neurons are the largest population and they pretty much are active, their normal function is what causes brain activity. It’s the regulation of that function, the fine-tuning of that function, where we use inhibitory neurons.”

By understanding how inhibitory neurons develop, Paredes hopes to shed new light on the origin of neurological disorders, like seizures or epilepsy.

If alcohol was not as readily available, would people's hearts be healthier? To find out, cardiologist Gregory Marcus of the University of California, San Francisco, looked to the state of Texas.

"We leveraged the fact that in Texas some counties don't allow access to alcohol, at least purchase of alcohol, and others counties do."

Since alcohol consumption is linked to cardiovascular disease, Marcus wanted to see if being in a dry county would affect the number of atrial fibrillation cases. This is the most common abnormal heart rhythm, which can cause stroke.

"And what we found in wet counties, meaning where there was no restriction on alcohol sale, that the prevalence and development of atrial fibrillation was more common than in the counties that prohibited sales of alcohol. At the same time we found that those wet counties also had less heart attacks or less myocardial infractions."

Marcus’ findings show that different people respond differently to alcohol. So if you’re wondering if your heart would benefit from moderate drinking, you should first find out if you’re at risk of developing heart disease.

Why do fools fall — and stay — in love?

University of California love experts chat with Science Today host, Larissa Branin, about the science behind romance. Originally broadcast as a Facebook Live video, this is the audio version of UC Berkeley psychologists and neurologists Arthur Aron, Robert Levenson and Emiliana Simon-Thomas discussing the drug-like effects of budding romance, and how that differs from the psychology and brain chemistry at work in a long-term relationship.

3D bioprinting is an emerging technology in which 3D printers are used with bio-inks to artificially construct living tissue by outputting layers of living cells. To do this, research engineer Monica Moya of the Lawrence Livermore National Laboratory says bioprinters need to output a dissolvable gel to support and protect cells during printing.

"So we have to keep them happy before they’re going to be printed, during the print process and then afterwards. And so during the print process, the biggest challenge that we have is when they’re going through those nozzles. We have to make sure that the gel is the right kind of consistency. So, it’s sort of a Goldilocks conundrum, where it has to be just right."

Too liquid and researchers have a puddle instead of a structure; too stiff and they can shear cells, causing them to burst and die. So, what is the right consistency?

"Well, it’s kind of like snot, where it’s a little bit formed but it’s still kind of liquid, enough so that the cells can come out in a liquid form."

Moya’s team has bioprinted an unorganized network of blood vessels – a feat that could someday revolutionize medical practice.

Certain medications may be bad for your teeth. In a new study, Peter Rechmann, a professor of dentistry at the University of California, San Francisco, found that patients who take, for example, blood pressure medicine or anti-anxiety drugs are more likely to develop cavities. This is because some of these drugs can cause dry mouth.

"What we do with each and every patient, when we figure out a caries risk, we let them spit in a tube and if they produce during two minutes around two millimeters of saliva per minute, that’s normal. Those with medication produce much less."

When there isn’t enough saliva, bacteria can run wild. And while this may damage your teeth with acid.

“Saliva protects your teeth because it has calcium, phosphate and fluoride in it and it helps to remineralize the tooth. “

So if you can’t get off medication, Rechmann recommends protecting your teeth with fluoride-rich toothpaste, mouthwash with chlorhexidine and chewing gum with xylitol.

Researchers have discovered a molecule that triggers Listeriosis, a foodborne infection caused by Listeria bacteria. The illness makes hundreds of Americans sick every year and pregnant women are especially vulnerable, since the infection can result in miscarriage and pre-term birth.

"The bacterium Listeria is actually ubiquitous. We can find it in the environment, in any kind of food products. And it can cause an occasional disease or it can cause outbreaks. There have been outbreaks associated with cantaloupes, with hotdogs.”

That’s microbiologist Anna BakArdjiev of the University of California, San Francisco. She explains their finding debunk previous theories that a pregnant woman’s weakened immune system could trigger the disease. By identifying the culprit as a bacterial protein, Bakardjiev says researchers now have more tools to fight Listeria.

"Could we use this protein and vaccinate people with this protein so the bacteria that infected the mother can be eliminated before they get into the placenta if they express the protein?"

If you could do something to avoid facing the dental drill, wouldn’t you do it? This week on Science Today, we chatted with Dr. Peter Rechmann of the UC San Francisco School of Dentistry about a new approach they’re using there called Caries Management by Risk Assessment, or CAMBRA. Basically, it means fighting cavities before they invade your teeth.

"You recommend to a patient some behavior change and additional chemical interventions like fluoride, which makes the teeth harder, like chlorhexidine, which kills bacteria."

Rechmann says adding chewing gum with xylitol can also save teeth in the pre-cavity stage. He’s even seen lesions in x-rays that would have otherwise called for the drill, completely disappear. So next time, you may want to think twice before passing up an offer for gum..just make sure it’s a brand with xylitol. Next, we visit UC Berkeley, where we learned how researchers there are designing a water filter made of a material so thin, it’s 2-dimensional. Baoxia Mi says they make these membrane filters by organizing the nanomaterial graphene oxide into single layers of carbon, and then stacking them together.

"This material has a lot of properties that are suitable for membrane filtration, especially for water purification – disinfection, absorption, or some other properties, that can help us enhance the removal of water contaminants."

Unlike current membrane filters, Mi’s design does not require as much energy to push the water through the membrane, since water passes quickly across graphene. Really, there’s so much exciting research like this going on like the University of California, so please come back for more. You can subscribe to Science Today on iTunes or follow us on Soundcloud. Until next time, I’m Larissa Branin.

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