Pulsed cavitation ultrasound (PCU) can be used to remotely soften human degenerative calcified biosprosthetic valves and may significantly improve the valve opening function, according to a study.
Olivier Villemain, MD, et al., examined the effects of PCU on human bioprosthetic heart valves that were removed from patients because they were heavily calcified and were non-functional. PCU, also called histotripsy, uses short-pulses of focused high pressure ultrasound to soften biological tissue. The ultrasound is delivered by a transducer that can be placed outside of the body and directed in a focused manner to the area of interest.
The removed valves were surgically implanted in sheep or were studied in an experimental bath apparatus in order to examine the longer-term effects of PCU. The researchers found that the PCU was able to soften the stiff calcified valves and improve the function of the valves. The amount of stenosis of the calcified aortic valves decreased by about two-fold on average in both the animal model and the experimental apparatus. The researchers believe that this new non-invasive approach has the potential to improve the outcome of patients with severe calcified bioprosthesis stenosis by avoiding risky surgical or transcatheter reintervention.
This study was designed as a proof of concept study and did not evaluate the potential risk of PCU causing pieces of the calcified aortic valve breaking off and causing an embolic stroke.
"The results of this experimental study must be regarded as provisional because neither the safety nor efficacy of this technique have been evaluated in humans," commented Douglas L. Mann, MD, FACC, editor-in-chief of JACC: Basic to Translational Science. "However, the concept of using high energy ultrasound to restore the function of calcified artificial tissue valves, analogous to the manner in which nephrologists use ultrasound to break up kidney stones, is both provocative and exciting. The ultrasound devices to perform this type of therapy exist today, so the ability to translate these concepts to patients can move very quickly."

American College of Cardiology www.acc.org/latest-in-cardiology/articles/2017/06/16/10/40/can-pulsed-cultivation-ultrasound-improve-valve-function?w_nav=LC

Robot-assisted laparoscopic surgery to remove a patient’s entire kidney requires slightly longer operating times and results in increased costs compared with the use of traditional laparoscopic surgery, according to a large, multiyear analysis conducted by researchers at the Stanford University School of Medicine.
However, the two approaches have comparable patient outcomes and lengths of hospital stay, the study showed. Laparoscopic surgery is a minimally invasive procedure in which surgical operations are done through small incisions. The removal of the entire kidney is called a radical nephrectomy.
“Although the laparoscopic procedure has been standard of care for a radical nephrectomy for many years, we saw an increase in the use of robotic-assisted approaches, and by 2015 these had surpassed the number of conventional laparoscopic procedures,” said Benjamin Chung, MD, associate professor of urology. “We found that, although there was no statistical difference in outcome or length of hospital stay, the robotic-assisted surgeries cost more and had a higher probability of prolonged operative time.”
The discrepancy may be due to the time needed for robotic operating room setup or due to a surgeon being in the earlier part of his or her learning curve, resulting in a subsequent increase in operating room and instrumentation costs, the researchers speculated.
Surgical robots are helpful because they offer more dexterity than traditional laparoscopic instrumentation and use a three-dimensional, high-resolution camera to visualize and magnify the operating field. Some procedures, such as the removal of the prostate or the removal of just a portion of the kidney, require a high degree of delicate manoeuvring and extensive internal suturing that render the robot’s assistance invaluable. But Chung and his colleagues wondered whether less technically challenging surgeries, such as the removal of a whole kidney, may not benefit as significantly from a robot’s help.
The researchers analysed data from 416 hospitals across the country from 2003 to 2015. They found that in 2003 about 65 percent of patients with kidney tumours that necessitated the removal of the entire organ underwent an open surgical procedure. About 34 percent had their kidney removed using a laparoscopic procedure, and only the remaining 1.5 percent of cases were conducted with robot-assisted surgery. By 2015, the proportion of patients who underwent the open procedure had decreased to about 50 percent, but the use of robot-assisted laparoscopic surgery for the remaining cases had surpassed that of traditional laparoscopic surgery, 27 percent to 23 percent.
When they pooled the data across the years, the researchers found that among nearly 24,000 patients, almost 19,000 underwent a traditional laparoscopic procedure and about 5,000 underwent a robotic-assisted procedure. They found that 46.3 percent of those patients whose surgeon used the robot had a total procedure time of more than four hours. In contrast, about 28.5 percent of the patients whose surgeon used the conventional laparoscopic procedure were in the operating room for more than four hours.
On average, the total hospital cost (including the cost of supplies, room and board, pharmaceuticals and operating room time) for the robot-assisted procedure exceeded that of the traditional laparoscopic procedures by about $2,700 per patient. The researchers speculated that the increased cost may be due to longer times spent in the operating room and the disposable instruments upon which surgical robots rely.
The increase in robot-assisted surgery for many procedures may be due to a variety of factors, the researchers said. The technology clearly benefits patients for certain types of surgeries. In other situations, there may be an expectation on the part of the hospital or the surgeons themselves to justify the large initial investment in purchasing the robot by using it for many types of procedures. And, regardless of the procedure, use of the robotic platform can assist the surgeon in many ways to make the operation more comfortable for the surgeon. Finally, patients themselves may view robot-assisted surgery as more technologically advanced.
Chung noted that the study covers a time period when many physicians were just learning to use the robots for this type of procedure; as time passes, it’s possible the operating time will decrease and that the cost differences between the two procedures will narrow. But for now, the study suggests that robot-assisted surgery isn’t always the right choice.
Stanford Medicine med.stanford.edu/news/all-news/2017/10/robot-assisted-surgery-for-kidney-removal-linked-to-longer-times.html

Cedars-Sinai neuroscience investigators have found that Alzheimer’s disease affects the retina – the back of the eye – similarly to the way it affects the brain. The study also revealed that an investigational, non-invasive eye scan could detect the key signs of Alzheimer’s disease years before patients experience symptoms.
Using a high-definition eye scan developed especially for the study, researchers detected the crucial warning signs of Alzheimer’s disease: amyloid-beta deposits, a buildup of toxic proteins. The findings represent a major advancement toward identifying people at high risk for the debilitating condition years sooner.
The study comes amid a sharp rise in the number of people affected by the disease. Today, more than 5 million Americans have Alzheimer’s disease. That number is expected to triple by 2050, according to the Alzheimer’s Association.
“The findings suggest that the retina may serve as a reliable source for Alzheimer’s disease diagnosis,” said the study’s senior lead author, Maya Koronyo-Hamaoui, PhD, a principal investigator and associate professor in the departments of Neurosurgery and Biomedical Sciences at Cedars-Sinai.
“One of the major advantages of analysing the retina is the repeatability, which allows us to monitor patients and potentially the progression of their disease.”
Yosef Koronyo, MSc, a research associate in the Department of Neurosurgery and first author on the study, said another key finding from the new study was the discovery of amyloid plaques in previously overlooked peripheral regions of the retina. He noted that the plaque amount in the retina correlated with plaque amount in specific areas of the brain.
“Now we know exactly where to look to find the signs of Alzheimer’s disease as early as possible,” said Koronyo.
Keith L. Black, MD, chair of Cedars-Sinai’s Department of Neurosurgery and director of the Maxine Dunitz Neurosurgical Institute, who co-led the study, said the findings offer hope for early detection when intervention could be most effective.
“Our hope is that eventually the investigational eye scan will be used as a screening device to detect the disease early enough to intervene and change the course of the disorder with medications and lifestyle changes,” said Black.

newswise
www.newswise.com/articles/noninvasive-eye-scan-could-detect-key-signs-of-alzheimer-s-disease-years-before-patients-show-symptoms
 

A team of engineering and medical researchers has found a way to use ultrasound to monitor fluid levels in the lung, offering a non-invasive way to track progress in treating pulmonary edema – fluid in the lungs – which often occurs in patients with congestive heart failure. The approach, which has been demonstrated in rats, also holds promise for diagnosing scarring, or fibrosis, in the lung.
“Historically, it has been difficult to use ultrasound to collect quantitative information on the lung, because ultrasound waves don’t travel through air– and the lung is full of air,” says Marie Muller, an assistant professor of mechanical engineering at North Carolina State University and co-author of a paper on the work. “However, we’ve been able to use the reflective nature of air pockets in the lung to calculate the amount of fluid in the lung.”
When ultrasound waves travel through the body, most of each wave’s energy passes through the tissue. But some of that energy is reflected as an echo. By monitoring these echoes, an ultrasound scanner is able to create an image of the tissue that the waves passed through. All of this happens in microseconds.
But when ultrasound waves hit air, all of the energy is reflected – which is why ultrasound images of the lung tend to look like a big, grey blob, with little useful information for healthcare providers. And while there are some techniques that allow users to determine if a patient has pulmonary edema, those techniques still can’t tell how much fluid there is.
This is where Muller’s team comes in.
When ultrasound waves hit air pockets in the lung, or alveoli, they scatter. Those scattered waves hit other air pockets, scattering them further. This process of bouncing around means that it takes an ultrasound’s echo much longer to bounce back to the ultrasound machine – though it’s still measured in microseconds. And that is why the lung looks like a grey blob to the ultrasound scanner.
But no two ultrasound waves take the same path – they may bounce in different directions as they travel through the lung. So their echoes take different amounts of time to return to the scanner. By looking at all of the echoes, and how those echoes change over time, Muller and her collaborators were able to calculate the extent to which the space between the air pockets was filled with fluid.
To test their approach, the researchers conducted two sets of experiments using rats and rat lung tissue.
In the first set of experiments, researchers used rat lung tissue that had been injected with saline solution to mimic fluid-filled lung tissue. The new approach allowed researchers to quantify the amount of fluid in the lung to within one milliliter.
In the second set of experiments, researchers found significant differences between fluid-filled and healthy lungs in rats. Specifically, the researchers were calculating the mean distance between two “scattering events” – or how far an ultrasound wave travelled between two air pockets.
For fluid-filled lungs, the mean distance was 1,040 micrometers, whereas the mean distance in healthy lungs was only 332 micrometers.
“This is important, because one could potentially track this mean distance value as a way of determining how well pulmonary edema treatment is working,” Muller says.
The technique makes use of conventional ultrasound scanning equipment, though the algorithm used by the researchers would need to be incorporated into the ultrasound software.

North Carolina State Universityhttp://tinyurl.com/ycktwghh 

One downside to medical sensors that test human sweat: You have to sweat. Sweating from exertion or a stifling room temperature can be impractical for some patients and unsafe for others. And unless they are on the second leg of the Tour de France, it’s unlikely patients will want to sweat all day for the benefit of a sensor reading.
But researchers at the University of Cincinnati have come up with a novel way to stimulate sweat glands on a small, isolated patch of skin so subjects can stay cool and comfortable and go about their daily routine without spending hours on a treadmill.
UC professor Jason Heikenfeld and UC graduate Zachary Sonner came up with a device the size of a Band-Aid that uses a chemical stimulant to produce sweat, even when the patient is relaxed and cool. The sensors also can predict how much patients sweat, an important factor in understanding the hormones or chemicals the biosensors measure.
"Doctors would love to know if chemical concentrations are increasing or decreasing over time," Heikenfeld said. "What was your baseline before you got sick? Then by measuring the change in concentrations, we know even more about how sick you are or how quickly you are getting better."
Blood analysis is considered the gold standard for biometric analysis. But biometric testing with blood is invasive and often requires the use of a lab. It is far more difficult for doctors to perform continuous monitoring of blood over hours or days.
Sweat provides a non-invasive alternative, with chemical markers that are more useful in monitoring health than saliva or tears, Heikenfeld said.
“People for a long time ignored sweat because, although it can be a higher-quality fluid for biomarkers, you can’t rely on having access to it,” Heikenfeld said. “Our goal was to achieve methods to stimulate sweat whenever needed — or for days.”
Scientists say sweat provides much of the same useful information about patients as blood. The problem has always been getting the same consistent sample as is possible with a standard blood draw, he said.
For the study, the researchers applied sensors and a gel containing carbachol, a chemical used in eyedrops, to their subject’s forearm for 2.5 minutes.
They used three methods to obtain sensor data: the gel and sensors alone and in combination with memory foam padding (to provide better contact between the sensor and the skin) and iontophoresis, an electrical current at 0.2 milliamps that drives a tiny amount of carbachol into the upper layer of the skin and locally stimulates sweat glands but causes no physical sensation or discomfort.
Then they recorded data obtained from the subject’s sweat for 30 minutes using sensors that measured concentrations of sweat electrolytes. Carbachol was effective at inducing sweating under the sensor for as long as five hours. Heikenfeld said a subsequent study successful generated sensor results for several days using this process to stimulate sweat.
They used a pH-sensitive dye to observe the results. The orange dye turned blue when it reacted with sweat. This demonstrated that the sweat glands were stimulated evenly across the sensor area.
“This work represents a significant leap forward in sweat-sensing technology,” the study concluded.

University of Cincinnati
magazine.uc.edu/editors_picks/recent_features/Sweat.html