Titanium is the leading material for artificial knee and hip joints because it’s strong, wear-resistant and nontoxic, but an unexpected discovery by Rice University physicists shows that the gold standard for artifi cial joints can be improved with the addition of some actual gold.
‘It is about 3-4 times harder than most steels,’ said Emilia Morosan, the lead scientist on a new study in Science Advances that describes the properties of a 3-to-1 mixture of titanium and gold with a specific atomic structure that imparts hardness. ‘It’s four times harder than pure titanium, which is what’s currently being used in most dental implants and replacement joints.’
Morosan, a physicist who specializes in the design and synthesis of compounds with exotic electronic and magnetic properties, said the new study is ‘a first for me in a number of ways. This compound is not difficult to make, and it’s not a new material.’ In fact, the atomic structure of the material – its atoms are tightly packed in a ‘cubic’ crystalline structure that’s oft en associated with hardness – was previously known. It’s not even clear that Morosan and former graduate student Eteri Svanidze, the study’s lead co-author, were the first to make a pure sample of the ultrahard ‘beta’ form of the compound. But due to a couple of lucky breaks, they and their co-authors are the fi rst to document the material’s remarkable properties.
‘This began from my core research,’ said Morosan, professor of physics and astronomy, of chemistry and of materials science and nano-engineering at Rice. ‘We published a study not long ago on titanium-gold, a 1-to-1 ratio compound that was a magnetic material made from nonmagnetic elements. One of the things that we do when we make a new compound is try to grind it into powder for X-ray purposes. This helps with identifying the composition, the purity, the crystal structure and other structural properties. ‘When we tried to grind up titanium-gold, we couldn’t,’ she recalled. ‘I even bought a diamond (coated) mortar and pestle, and we still couldn’t grind it up.’
What the team didn’t know at the time was that making titanium- 3-gold at relatively high temperature produces an almost pure crystalline form of the beta version of the alloy – the crystal structure that’s four times harder than titanium. At lower temperatures, the atoms tend to arrange in another cubic structure – the alpha form of titanium-3-gold. The alpha structure is about as hard as regular titanium. It appears that labs that had previously measured the hardness of titanium-3-gold had measured samples that largely consisted of the alpha arrangement of atoms.
The team measured the hardness of the beta form of the crystal in conjunction with colleagues at Texas A&M University’s Turbomachinery Laboratory and at the National High Magnetic Field Laboratory at Florida State University; Morosan and Svanidze also performed other comparisons with titanium. For biomedical implants, for example, two key measures are biocompatibility and wear resistance. Because titanium and gold by themselves are among the most biocompatible metals and are oft en used in medical implants, the team believed titanium-3-gold would be comparable. In fact, tests by colleagues at the University of Texas MD Anderson Cancer Center in Houston determined that the new alloy was even more biocompatible than pure titanium. The story proved much the same for wear resistance: Titanium-3-gold also outperformed pure titanium.

Rice University http://tinyurl.com/jto5exc

‘Atrial fibrillation is thought to be responsible for 20 to 30 percent of all strokes in the United States,’ said Northwestern’s Michael Markl, the Lester B. and Frances T. Knight Professor of Cardiac Imaging. ‘While atrial fibrillation is easy to detect and diagnose, it’s not easy to predict who will suffer a stroke because of it.’

Markl, who is a professor of biomedical engineering in the McCormick School of Engineering and of radiology in the Feinberg School of Medicine, has developed a new imaging technique that can help predict who is most at risk for stroke. This breakthrough could lead to better treatment and outcomes for patients with atrial fibrillation.

Atrial fibrillation is linked to stroke because it slows the patient’s blood flow. The slow, sluggish blood flow can lead to blood clots, which can then travel to the brain and initiate stroke. Markl’s cardiac magnetic resonance (CMR) imaging test can detect the blood’s velocity through the heart and body. Called ‘atrial 4D flow CMR,’ the technique is non-invasive and does not require contrast agents. The imaging program, which images blood flow dynamically and in the three spatial dimensions, comes in the form of software that can also be integrated into current MRI equipment without the need of special hardware and scanners or equipment upgrades.

4D flow CMR can be employed to measure in-vivo 3D blood flow dynamics in the heart and atria. Derived flow stasis maps in the left atrium and left atrial appendage are a novel concept to visualize and quantify regions with low flow, known to cause clot formation and risk for stroke.
‘We simply programmed the scanner to generate information differently – in a way that wasn’t previously available,’ Markl said. ‘It allows you to measure flow, diffusion of molecules, and tissue elasticity. You can interrogate the human body in a very detailed manner.’

Historically, physicians have attempted to assess stroke risk in atrial fibrillation patients by using a risk scoring system, which takes risk factors, such as age, general health, and gender, into account. Higher risk patients are then given medicine to prevent blood clots that lead to stroke.

‘It’s very well accepted that these therapies significantly reduce the risk of stroke,’ Markl said. ‘But they also increase risk of bleeding complications. It’s a dilemma that physicians face. They want to reduce one risk without introducing another risk. It’s particularly difficult for younger patients who might be on these medications for a long period of time. Maybe the risk of bleeding is initially small. But after taking medication for 20 or 30 years, it’s more and more likely that they’ll experience complications.’

Markl’s 4D flow imaging technique can give a more precise assessment of who needs the medication, preventing physicians from over treating their patients. In a pilot study with 60 patients and a control group, Markl found that atrial fibrillation patients who would have been considered high risk for stroke by the traditional scoring system in fact had normal blood flow, while patients who were considered lower risk sometimes had the slow blood flow indicative of potential clotting.

‘About 50 or 60 percent of patients who you would consider high risk actually had normal flows,’ Markl said. ‘You could then hypothesize that those 50 percent don’t really need the treatment.’

Northwestern University www.mccormick.northwestern.edu/news/articles/2016/10/imaging-stroke-risk-in-4d.html

The Eustachian tube is the main connection between the back of the throat and the middle of the ear. Normally, the tube is filled with air and opens when yawning or chewing. “This allows you to equalize pressure” on either side of the eardrum, explained David Kaylie, MD, a Duke otolaryngologist. When the tube is blocked from a cold or sinus, nose or ear infection, air can no longer pass through. Stuffy ears and noses, hearing loss, ear pain and pressure, as well as ringing in the ears (tinnitus) can result.
Blocked Eustachian tubes can be relieved by nasal sprays and antihistamine tablets, which reduce inflammation and congestion. Recurrent Eustachian tube dysfunction requires the surgical placement of tubes in the eardrum, which allows pressure to equalize in the middle ear. Now that the FDA has approved the Aera system, children, and adults with chronic Eustachian tube dysfunction, can opt for a simple, 10-minute procedure instead, Kaylie said.
“This new device has been shown to return the middle ear to normal and greatly eliminate middle ear pressure in properly selected patients,” he said. Studies of the device showed “long term normal Eustachian function after the procedure.”
David Kaylie, MD, performs the minimally invasive procedure in the OR, but no overnight stay is required.
During the minimally invasive procedure, a catheter is used to insert a small balloon through the nose and into the Eustachian tube. The balloon is inflated, which opens the Eustachian tube and allows air to flow through. Once the tube is open, the balloon is deflated and removed.
While Kaylie believes the device will prove useful to many people who currently require ear tube surgery due to Eustachian tube dysfunction, fluid in their ears, or chronic ear infections, he also cautions that there are some people for whom it will not be appropriate. During the clinical trial for the Aera system, some common problems included small tears in the lining of the Eustachian tube, minor bleeding and, sometimes, worsening or their Eustachian tube dysfunction.
Still, Kaylie believes it will be a significant advance for the millions of people who require ear tube surgery. “There are people who need tubes 13 or 14 times,” he said. “Every time the tubes come out, they need the tubes in again. There is a huge need for this procedure, and it will greatly reduce the need for all those ear tubes” and other related surgeries.

Duke Universityhttp://tinyurl.com/yanrxgb8

In a first-of-its-kind study, Mount Sinai researchers have discovered a novel technique to monitor laryngeal and vagus nerve function while patients are under anaesthesia during otolaryngology and neurosurgery procedures. The findings could save patients from vocal paralysis, maintain their swallowing function, and transform the way doctors perform surgeries.
Laryngeal nerve injuries following thyroid or anterior cervical spine surgeries affect approximately 10 percent of patients. To prevent these injuries, doctors typically monitor these nerves intermittently by stimulating them at various times through the procedure. But with intermittent monitoring, a possible nerve injury can be missed. Continuous stimulation allows doctors to see damage before it occurs and take preventative measures, but until now the only method of continuous monitoring has required doctors to place an electrode around the vagus nerve in the neck (this cranial nerve extends from the brainstem to the abdomen and helps supply voice and swallowing functions and control heart, lungs and digestion), which is invasive for the patient and can cause surgical complications.
Mount Sinai researchers recently developed a new, less invasive technique to continuously oversee the nerve function throughout thyroid procedures and cervical spine fusions. This novel technique relies solely on a special type of breathing or endotracheal tube, inserted by the anaesthesiologist at the start of the surgical procedure. They use the tube to both stimulate and monitor nerve responses during the entire surgery, which has never been done before. This technique allows surgeons to see how different surgical manoeuvres affect nerve function, and then change their approach to prevent post-surgical voice and swallowing complications resulting from nerve dysfunction during the procedure. According to their research results, this technique may improve patient outcomes and lower complication rates.
"This simple technique will likely have wide-reaching effects by greatly enhancing our ability to monitor the vagus nerve in the head and neck during neurosurgical and cardiothoracic surgeries. It requires no equipment other than a monitored breathing tube, and this type of tube is generally already used in most of these surgeries," said lead investigator Catherine Sinclair, MD, FRACS, Assistant Professor, Otolaryngology, Icahn School of Medicine at Mount Sinai. "Never before have we been able to monitor both sensory and motor branches of the vagus nerve. The ability to monitor sensory function for the first time is a huge breakthrough and will hopefully translate into improved patient outcomes."

EurekAlert
www.eurekalert.org/pub_releases/2017-07/tmsh-ms062617.php

A team led by researchers from the Stanford University School of Medicine has demonstrated a way to diagnose cancer without resorting to surgery, raising the possibility of far fewer biopsies.

For this first-in-humans clinical trial, women with either breast or ovarian tumours were injected intravenously with microbubbles capable of binding to and identifying cancer.

Jurgen Willmann, MD, a professor of radiology at Stanford, is lead author, and Sanjiv ‘Sam’ Gambhir, MD, PhD, professor and chair of radiology, is the senior author of the study.

For the study, 24 women with ovarian tumours and 21 women with breast tumours were intravenously injected with the microbubbles. Clinicians used ordinary ultrasound to image the tumours for about a half-hour after injection. The high-tech bubbles clustered in the blood vessels of tumours that were malignant, but not in those that were benign.

The ultrasound imaging of patients’ bubble-labelled tumours was followed up with biopsies and pathology studies that confirmed the accuracy of the diagnostic microbubbles.

Medical microbubbles are spheres of phospholipids, the same material that makes up the membranes of living cells. The bubbles are 1 to 4 microns in diameter, a little smaller than a red blood cell, and filled with a harmless mixture of perfluorobutane and nitrogen gas.

Ordinary microbubbles have been approved by the Food and Drug Administration and in clinical use for several years now. But such microbubbles, a kind of ultrasound ‘contrast agent,’ have only been used to image organs like the liver by displaying the bubbles as they pass through blood vessels. Up to now, the bubbles couldn’t latch onto blood vessels of cancer in patients.

The microbubbles used in this study were designed to bind to a receptor called KDR found on the tumour blood vessels of cancer but not in healthy tissue. Noncancerous cells don’t have such a receptor. Under ultrasound imaging, the labelled microbubbles, called MBKDR, show up clearly when they cluster in a tumour. And since benign breast and ovarian tumours usually lack KDR, the labelled microbubbles mostly passed them by.

In this small, preliminary safety trial, the technique appeared to be both safe and very sensitive, said Willmann, who is chief of the Division of Body Imaging at Stanford. And it also works with ordinary ultrasound equipment. ‘So, there’s no new ultrasound equipment that needs to be built for that,’ he said. ‘You can just use your regular ultrasound and turn on the contrast mode – which all modern ultrasound equipment has.’

Stanford Medicinemed.stanford.edu/news/all-news/2017/04/ultrasound-and-microbubbles-flag-malignant-cancer-in-humans.html