Archive for April 2018

Dentistry in the hospital: A Q&A

April 18, 2018

Photo of Dyani Gaudilliere (right) in OR; by Vladimir Nekhendzy

In the U.S., medicine and dentistry are separate — they typically have different insurance systems, training regimes and workplaces. So I was intrigued when I heard about hospital dentists. To learn more about what they do, I spoke with Dyani Gaudilliere, DMD, a clinical assistant professor of surgery and chief of the dental section at Stanford.

Why did you choose to combine dentistry with medicine?

“I started on the path towards dentistry in my teens, planning to become an orthodontist. I became increasingly interested in public health, with the goal of treating underserved populations.

At my dental school (Harvard), the dental and medical school courses were combined for the first two years with the goal of fostering a more integrated approach to dentistry, which prepared me well for my current work.

The split between medicine and dentistry is, in fact, completely artificial. The bacterial diseases of the teeth and gingiva affect the entire immune system and can cause serious systemic consequences. In addition, many systemic diseases and medications have oral manifestations.”

What do you do at Stanford?

“The majority of our patients at Stanford are being treated for cancer, organ transplantation, cardiac disease or joint replacement. Our goal is to rid these patients of bacterial disease in their teeth and gums prior to their treatments. It may be risky to treat them outside the hospital, without access to the their full medical records or emergency services. Lack of dental insurance can also be a barrier for patients whose chronic disease prevents them from being employed.”

Can you tell me more about your patients?

“One large category of patients we see are those with cancer of the head and neck. Targeted radiation to this area and chemotherapy have serious long-term side effects, ranging from dry mouth resulting in rampant tooth decay to severe jaw infections. For this reason, we perform dental examination and patient education prior to these treatments. We also partner with the head and neck surgeons to remove infected teeth during their cancer resection surgery. And we create special oral positioning devices to aid the radiation oncologists in spacing and immobilizing the tissues during radiation therapy.

We also see patients before medical treatments that will leave them immunocompromised, such as chemotherapy or organ transplantation. Chronic tooth or gum infections can suddenly become life threatening in a patient who is immunocompromised.

A third example is trauma. It is common for patients to get in minor bike accidents and fly right over their handlebars onto their teeth. We see these patients in the emergency department urgently in order to put the teeth and supporting bone back into place and then stabilize them with cemented splints.”

Are there many hospital dentists?

“I believe there isn’t enough awareness of the medical necessity of dental care, nor are there enough hospital dentists. Some hospitals are lucky to be affiliated with dental schools, whereas most have no in-house or emergency dental team at all. We regularly receive patients transferred from outside hospitals with large infections or oral trauma, because these hospitals didn’t have anybody with the right expertise to treat the conditions.

There are a lot of barriers we need to cross in order to fully integrate dentistry and medicine, but I think this integration is way overdue.”

What is your view on the separation between dentistry and medicine?

“The reason for the separation seems to be a combination of history and politics. Tooth extractions and other surgeries were historically performed by barber-surgeons rather than physicians, and oral care developed as a separate track from care of literally every other part of the body. Fast forward to today and you have dentists lobbying to sustain this separation in order to spare their profession from the regulations and changes occurring in the medical care world.

The idea that dentists would not need medical knowledge is laughable considering how much surgery they perform. Dentists who don’t understand medications and their mechanisms would not last long after their patient on blood thinners loses pints of blood after an extraction.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

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“A toxicological experiment:” Additional study needed on e-cigarettes use

April 12, 2018

Photo by Itay Kabalo

Although the market for e-cigarettes is booming, scientists and health agencies are still debating the extent of their health impacts. Basic questions remain: What chemicals are in the vapor cloud produced by e-cigarettes? And how does this vapor affect users and those around them?

A research team led by Hugo Destaillats, PhD, a chemist in the Indoor Environment Group at Lawrence Berkeley National Lab, is seeking the answers to these questions.

Destaillats and his colleagues have studied the complex chemical composition of vaping aerosols, the cloud of particles the devices emit. In one study, they quantified emissions from three e-liquids with various vaporizers, battery power settings and vaping habits — ranging from heavy to low puff duration and frequency.

The researchers found 31 potentially toxic substances in the vapors, including two not previously detected: propylene oxide in the e-liquids and glycidol in the vapors. Both of these compounds are considered probable carcinogens. They also determined that the base fluids used in vaping, propylene glycol and glycerin, can decompose when heated to produce acrolein, a powerful irritant.

However, the level of these toxins varied depending on the type of e-cigarette and how it was operated. For instance, toxic emissions rates were higher for e-cigarettes with a single heating coil compared to ones with double coils. Toxin levels also increased with the voltage used to power the device. And they rose with repeated use, presumably due to a buildup of residue within the device.

“We hope that one outcome of our research has been to provide useful information to manufacturers to help them improve the safety of their devices,” said Destaillats in a recent article in Analytical Scientist. .

In a follow-up study, the researchers assessed the health impact of firsthand and secondhand exposure to these vapor clouds under various typical use conditions. The integrated health damage from vaping for the various scenarios was lower than, or comparable to, the estimated damage from tobacco smoke, they concluded.

Given the countless unique e-liquid flavors and the on-going development of new devices, this research is difficult to generalize, they said, but they are concerned that more unidentified toxins exist.

Destaillats summarized in the article:

“Vaping is effectively a toxicological experiment being carried out with millions of people around the world.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

New way to understand tumor diversity combines CRISPR with genetic barcodes

April 10, 2018

Photo courtesy of PIXNIO

The growth of a particular tumor depends on multiple genetic factors, so it is difficult for cancer researchers to recreate and study this genetic diversity in the lab.

“Human cancers don’t have only one tumor-suppression mutation [which fuels tumor growth] — they have combinations. The question is, how do different mutated genes cooperate or not cooperate with one another?” said Monte Winslow, PhD, a Stanford assistant professor of genetics and of pathology, in a recent Stanford news release.

Now, Winslow and his colleagues have discovered a way to modify cancer-related gene and then track how these combinations of mutations impact tumor growth, as recently reported in Nature Genetics.

The researchers used a powerful gene-editing tool, called CRISPR-Cas9, to introduce multiple, genetically distinct tumors in the lungs of mice. They also attached short, unique DNA sequences to individual tumor cells — which acted as genetic barcodes and multiplied in number as the tumors grew. By counting the different barcodes, they were able to accurately and simultaneously track tumor growth.

“We can now generate a very large number of tumors with specific genetic signatures in the same mouse and follow their growth individually at scale and with high precision. The previous methods were both orders of magnitude slower and much less quantitative,” said Dmitri Petrov, PhD, a senior author of the study and an evolutionary biologist at Stanford, in the release.

The study showed that many tumor-suppressor genes only drive tumor growth when other specific genes are present. The researchers hope to use their new methodology to better understand why tumors with the same mutations sometimes grow to be very large in some patients and remain small in others, they said.

Their technique may also speed up cancer drug development, allowing a drug to be tested on thousands of tumor types simultaneously. Petrov explained in the release:

“We can help understand why targeted therapies and immunotherapies sometimes work amazingly well in patients and sometimes fail. We hypothesize that the genetic identify of tumors might be partially responsible, and we finally have a good way to test this.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Oncologist disagree on use of value to guide cancer treatments

April 5, 2018

Cancer care is expensive, with the cost of new chemotherapies exceeding  $100,000 annually and the growth in cancer care costs increasing faster than the growth in general medical care costs. In addition, there is a widely acknowledged mismatch between the costs and benefits of treatment.

“The pricing of cancer drugs doesn’t appear to be related to their health benefit. This is problematic and unaffordable both for the health care system and for patients, who are expected to engage in not-insubstantial cost sharing,” explained Risha Gidwani-Marszowski, DrPH, a health economist at the VA Palo Alto Health Care System and at Stanford.

In response to this gap, oncology professional societies now recommend that oncologists consider the value of a treatment when making clinical recommendations, a major shift in clinical practice. But how are oncologists defining whether a therapy has “high value?” And how are they using this information?

Gidwani-Marszowski investigated these questions in a new study recently published in Value in Health. Her multi-institutional research team conducted in-depth interviews with 31 U.S. oncologists who practiced in a diverse range of environments, including academic medical centers, community medical centers and the Veterans Health Administration.

The researchers asked oncologists open-ended questions about larger questions regarding value – specifically,  about the oncologists’ definitions and measurements of value, as well as about their value-based choices.

“We didn’t want to operate under the erroneous assumption that we knew everything there is to know about the relevant features of the value problem,” said Gidwani-Marszowski. “We felt it would be better to keep things open-ended, so that practicing oncologists could tell us the aspects of value that were most relevant or salient to them.”

Once these in-depth conversations were transcribed, two independent investigators qualitatively assessed the transcripts to identify themes — pinpointing and recording patterns. Their analyses revealed that oncologist have wide ranging views. Gidwani-Marszowski explained:

“One of the most interesting things we found through this work is that the divergent views exist at a very basic level — the definition of value.  For example, in defining value, some oncologists said cost was one of multiple factors that should be considered, while others said cost had no role at all to play in value.”

Additionally, some oncologists looked at cost in relation to a patient’s quality of life, while others looked at quality of life alone to measure value. One oncologist explained in the paper, “I think [value] shouldn’t just be measured by overall survival, but quality of life has to really be integrated into that. I’m extending the patient’s life by two months, if they’re filled with chemotherapy side effects and toxicity, have we increased the value?”

The oncologists also disagreed on how value should be measured, who should assess the value of a treatment and whether value should be discussed with the patient.

For one oncologist, conversations about costs are important: “I tend to explain to them what the cost is and what the benefit is. And some patients actually say, ‘I don’t think it’s worth it.’ … So I will give them [information about the] cost and the side effects and the benefit and we’ll make the decision together.”

For another oncologist, the conversations don’t work well: “Most of the time we don’t [discuss the cost of care] because then the patients and families think hey, these guys are looking at dollars and not providing the care… So that’s kind of really controversial. Plus it’s very uncomfortable even to talk about the money and the care we provide to them…”

Now, the team is using the results from these in-depth interviews to design a closed-ended survey, which they plan to disseminate to a large sample of oncologists across the country. Gidwani-Marszowski explained:

“Oncologists often have the best understanding of the effectiveness of a particular drug in a specific patient and largely guide the purchasing of care for cancer patients. Thus, it is partly through understanding their perspectives that we can improve the value of cancer care.”

Gidwani-Marszowski also told me that for value efforts to be successful, a critical first step is to make sure all of the relevant stakeholders — oncologists, patients, caregivers, other health care providers, payers, health economists and policy makers  — are able to reach a consensus on the definition of value in cancer care.  That will build a foundation for efforts to establish thresholds for value, mechanisms to measure value, and ultimately, efforts to improve the value of cancer care, she said.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Stanford and Common Sense Media explore effects of virtual reality on kids

April 4, 2018

Photo by Andri Koolme

Although we’re still a long ways off from the virtual reality universe depicted in the new movie “Ready Player One,” VR is becoming a reality in many homes. But how is this immersive technology impacting our kid’s cognitive, social and physical well-being?

Stanford researchers and Common Sense Media are investigating the potential effects of virtual reality on children. And a  just-released report provides parents and educators with a practical guide on VR use.

“The truth is, when it comes to VR and kids, we just don’t know that much. As a community, we need more research to understand these effects,” Jeremy Bailenson, PhD, a Stanford communication professor and the founder of Stanford’s Virtual Human Interaction Lab, wrote in an introduction to the report.

The research team surveyed over 3600 U.S. parents about their family’s use of virtual reality. “Until this survey, it was unclear how, and even how many, kids were using virtual reality,” said Bailenson in a recent Stanford news release. “Now we have an initial picture of its adoption and use.”

The report summarizes results from this survey and previous VR research. Here are its key findings:

  • VR powerfully affects kids, because it can provoke a response to virtual experiences similar to actual experiences.
  • Long-terms effects of VR on developing brains and health are unknown. Most parents are concerned, and experts advocate moderation and supervision.
  • Only one in five parents report living in a household with VR and their interest is mixed, but children are
  • Characters in VR may be especially influential on young children.
  • Students are more enthusiastic about learning while using VR, but they don’t necessarily learn more.
  • VR has the potential to encourage empathy and diminish implicit racial bias, but most parents are skeptical.
  • When choosing VR content, parents should consider whether they would want their children to have the same experience in the real world.

Ultimately, the report recommends moderation. “Instead of hours of use, which might apply to other screens, think in terms of minutes,” Bailenson wrote. “Most VR is meant to be done on the five- to 10-minute scale.”  At Stanford’s Virtual Human Interaction Lab, even adults use VR for 20 minutes or less.

One known potential side effect from overuse is simulator sickness, which is caused by a lag in time between a person’s body movements and the virtual world’s response. Some parents also reported that their child experienced a headache, dizziness or eye strain after VR use.

In addition, the researchers advise parents to consider safety. Virtual reality headsets block out stimuli from the physical world, including hazards, so users can bump into things, trip or otherwise harm themselves.

A good option, they wrote, is to bring your child to a location-based VR center that provides well-maintained equipment, safety spotters and social interactions with other kids.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.


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