Tag: 15/7/21

Categories : Implants and ProsthesesTags :

Liquid Metal Sensors Recreate a Sense of Touch

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Photo by ThisisEngineering RAEng on Unsplash
Photo by ThisisEngineering RAEng on Unsplash

To recreate a sense of ‘touch’, researchers have incorporated stretchable tactile sensors using liquid metal on the fingertips of a prosthetic hand. 

When manipulating an object, humans are heavily reliant on sensation in their fingertips, each of which has over 3000 pressure-sensitive touch receptors. While there are many high-tech, dexterous prosthetics available today, they all lack the sensation of ‘touch‘, resulting in objects inadvertently being dropped or crushed by a prosthetic hand.
To make a prosthetic hand interface that feels more natural and intuitive, researchers from Florida Atlantic University’s College of Engineering and Computer Science and collaborators incorporated stretchable tactile sensors using liquid metal on a prosthetic hand’s fingertips. Encapsulated within silicone-based elastomers, this technology provides key advantages over traditional sensors, including high conductivity, compliance, flexibility and stretchability.

For the study, published in the journal Sensors, researchers used individual fingertips on the prosthesis to distinguish between different speeds of a sliding motion along different textured surfaces. The four different textures had one variation: the distance between the ridges. To detect the textures and speeds, researchers trained four machine learning algorithms. For each of the ten surfaces, 20 trials were performed to test the ability of the machine learning algorithms to distinguish between the different textured surfaces.

Results showed that integrating tactile information from the fingertip sensors simultaneously distinguished between complex, multi-textured surfaces – demonstrating a new form of hierarchical intelligence. The algorithms could accurately distinguish between the fingertip speeds. This new technology could improve prosthetic hand control and provide haptic feedback for amputees to restore a sense of touch.

“Significant research has been done on tactile sensors for artificial hands, but there is still a need for advances in lightweight, low-cost, robust multimodal tactile sensors,” said senior author Erik Engeberg, PhD, an associate professor in the Department of Ocean and Mechanical Engineering. “The tactile information from all the individual fingertips in our study provided the foundation for a higher hand-level of perception enabling the distinction between ten complex, multi-textured surfaces that would not have been possible using purely local information from an individual fingertip. We believe that these tactile details could be useful in the future to afford a more realistic experience for prosthetic hand users through an advanced haptic display, which could enrich the amputee-prosthesis interface and prevent amputees from abandoning their prosthetic hand.”

Researchers compared four different machine learning algorithms for their successful classification capabilities. The time-frequency features of the liquid metal sensors were extracted to train and test the machine learning algorithms. Of these, a neural network algorithm generally performed the best at the speed and texture detection with a single finger and had a 99.2 percent accuracy to distinguish between ten different multi-textured surfaces using four liquid metal sensors from four fingers simultaneously.

“The loss of an upper limb can be a daunting challenge for an individual who is trying to seamlessly engage in regular activities,” said Stella Batalama, Ph.D., dean, College of Engineering and Computer Science. “Although advances in prosthetic limbs have been beneficial and allow amputees to better perform their daily duties, they do not provide them with sensory information such as touch. They also don’t enable them to control the prosthetic limb naturally with their minds. With this latest technology from our research team, we are one step closer to providing people all over the world with a more natural prosthetic device that can ‘feel’ and respond to its environment.”

Source: Florida Atlantic University

Journal information: Abd, M.A., et al. (2021) Hierarchical Tactile Sensation Integration from Prosthetic Fingertips Enables Multi-Texture Surface Recognition. Sensors. doi.org/10.3390/s21134324.

Categories : Diseases, Syndromes and ConditionsTags :

New Insights into Gum Disease and Inflammatory Response

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Photo by Caroline LM on Unsplash
Photo by Caroline LM on Unsplash

A team of researchers has identified how different people respond to the accumulation of dental plaque, helping us understand the vulnerability of some to serious conditions that lead to tooth loss and other problems. 

The study was led by University of Washington researchers and recently published in the journal Proceedings of the National Academy of Sciences (PNAS). 

Buildup of plaque, the sticky biofilm covering teeth and gums, can induce gingivitis, or gum inflammation if left unchecked. Gingivitis, in turn, can lead to periodontitis, a serious infection that can damage and destroy the gum and bones supporting teeth. As well as causing tooth loss, this chronic inflammation can also trigger heart disease, diabetes, cancer, arthritis, and bowel diseases.

The researchers also discovered a range of inflammatory responses to oral bacterial accumulation. When bacteria build up on tooth surfaces, it generates inflammation as the body responds. Two known major oral inflammation phenotypes were known: a high or strong clinical  response and a low clinical response. The team identified a third phenotype, which they dubbed ‘slow’: a delayed strong inflammatory response in the wake of the bacterial buildup.

The study also found that subjects with low clinical response also showed a low inflammatory response for a variety of inflammation signals.  “Indeed, this study has revealed a heterogeneity in the inflammatory response to bacterial accumulation that has not been described previously,” said Dr Richard Darveau of the UW School of Dentistry, one of the study’s authors.

Study co-author Dr Jeffrey McLean said, “We found a particular group of people that have a slower development of plaque as well as a distinct microbial community makeup prior to the start of the study.” The authors wrote that understanding the variations in gum inflammation could help screen for higher periodontitis risk. In addition, it is possible that this variation in the inflammatory response among the human population may be related to the susceptibility to other chronic bacterial-associated inflammatory conditions such as inflammatory bowel disease.

Additionally, the researchers found a novel protective response by the body, triggered by plaque accumulation, that can save tissue and bone during inflammation. This mechanism, which was apparent among all three phenotypes, utilises white blood cells known as neutrophils. In the mouth, they act something like cops on the beat, patrolling and regulating the bacterial population to maintain a stable condition known as healthy homeostasis.

In this instance, plaque is not a villain. To the contrary, the researchers said that the proper amount and makeup of plaque supports normal tissue function. Studies in mice have also shown that plaque also provides a pathway for neutrophils to migrate from the bloodstream through the gum tissue and into the crevice between the teeth and gums.

When healthy homeostasis exists and everything is working right, the neutrophils promote colonization resistance, a low-level protective inflammatory response that helps the mouth fend off an excess of unhealthy bacteria and resist infection. At the same time, the neutrophils help ensure the proper microbial composition for normal periodontal bone and tissue function.

The researchers’ findings underscore why dentists preach the virtues of regular brushing and flossing, which prevent too much plaque buildup. “The idea of oral hygiene is to in fact recolonise the tooth surface with appropriate bacteria that participate with the host inflammatory response to keep unwanted bacteria out,” Dr Darveau explained. The bacteria start repopulating the mouth’s surfaces spontaneously and almost immediately afterward, Dr Darveau said.

Source: University of Washington School of Dentistry

Journal information: Bamashmous, S., et al. (2021) Human variation in gingival inflammation. PNAS. doi.org/10.1073/pnas.2012578118.

Categories : Antibiotics Obstetrics & Gynaecology PaediatricsTags :

In Utero or Neonatal Antibiotic Exposure Could Lead to Brain Disorders

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Image by Ahmad Ardity from Pixabay
Image by Ahmad Ardity from Pixabay

According to a new study, antibiotic exposure early in life could alter human brain development in areas responsible for cognitive and emotional functions.

The study suggests that penicillin alters the body’s microbiome as well as gene expression, which allows cells to respond to its changing environment, in key areas of the developing brain. The findings, published in the journal iScience, suggest reducing widespread antibiotic use or using alternatives when possible to prevent neurodevelopment problems.
Penicillin and related medicines, such as ampicillin and amoxicillin, are the most widely used antibiotics in children worldwide. In the United States, the average child receives nearly three courses of antibiotics before age 2, and similar or greater exposure rates occur elsewhere.

“Our previous work has shown that exposing young animals to antibiotics changes their metabolism and immunity. The third important development in early life involves the brain. This study is preliminary but shows a correlation between altering the microbiome and  changes in the brain that should be further explored,” said lead author Martin Blaser, director of the Center for Advanced Biotechnology and Medicine at Rutgers.

In the study, mice were exposed to low-dose penicillin in utero or immediately after birth. Researchers found that, compared to the unexposed controls, mice given penicillin had large changes in their intestinal microbiota, with altered gene expression in the frontal cortex and amygdala. These two key brain areas are responsible for the development of memory as well as fear and stress responses.

Increasing evidence links conditions in the intestine to the brain in the ‘gut-brain axis‘. If this pathway is disturbed, it can lead to permanent altering of the brain’s structure and function and possibly lead to neuropsychiatric or neurodegenerative disorders in later childhood or adulthood.

“Early life is a critical period for neurodevelopment,” Blaser said. “In recent decades, there has been a rise in the incidence of childhood neurodevelopmental disorders, including autism spectrum disorder, attention deficit/hyperactivity disorder and learning disabilities. Although increased awareness and diagnosis are likely contributing factors, disruptions in cerebral gene expression early in development also could be responsible.”

Whether it is antibiotics directly affecting brain development or if molecules from the microbiome travelling to the brain, disturbing gene activity and causing cognitive deficits needs to be determined by future studies.

Source: Rutgers University-New Brunswick

Categories : COVID VaccinesTags :

ImmunityBio COVID Booster Gets Go-ahead for South African Trials

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Photo by Mufid Majnun on Unsplash
Photo by Mufid Majnun on Unsplash

Immunotherapy company ImmunityBio has been authorised by the South Africa Health Products Regulatory Authority (SAHPRA) to proceed with the South Africa Sisonke T-Cell Universal Boost trial. 

The Phase 1/2/3 study, starting in the second third quarter of 2021, is designed to evaluate hAd5 Spike + Nucleocapsid (S+N) as a boost for South African healthcare workers previously vaccinated with an S (Spike)-only vaccine.

“With the virus continuing to spread, moving forward with this boost trial is crucial,” said Leonard Sender, MD, Chief Operating Officer of ImmunityBio. “We are encouraged by the preliminary safety findings in our ongoing Phase 1 studies in both the U.S. and South Africa. In addition, our U.S. data show that just a single prime subcutaneous vaccination with our COVID-19 vaccine candidate induces a 10-fold increase in T cell response—equivalent to T cell responses from patients previously infected with SARS-CoV-2. We have also shown that the T-cell responses are maintained against variants, which is critical to providing protection against this ever-changing virus.”

In the trial, the effect of combining vaccination by subcutaneous (SC) and sublingual (SL) routes will be assessed. This combination has the potential to deliver protection from the virus with a single injection followed by droplets placed under the tongue. Methods that do not require injection such as SL, intranasal, and oral capsule offer potential advantages depending on the participant’s needs or situation. Sublingual administration offers the most rapid absorption, while nasal spray or oral capsule delivery have the potential to provide mucosal immunity, which could reduce both the chance of infection and potential spread of the virus via the respiratory tract. The three non-injection formulations do not need a trained healthcare worker to administer them and are easier to transport and store. The SL and nasal routes of administration are also currently being tested in a separate Phase 1 trial in South Africa.

“The number of new cases in South Africa is frightening, particularly when you consider recent data suggesting currently available COVID-19 vaccines may not provide the immune memory needed to fend off infection from future variants. This highlights an urgent need for a boost dose that confers long-term protection by activating both antibodies and T cells, ” said Patrick Soon-Shiong, MD, Founder and Executive Chairman of ImmunityBio.

“Several peer-reviewed studies demonstrate that patients who have recovered from SARS-CoV in the 2003 outbreak possess long lasting memory T cells reactive to the nucleocapsid protein of SARS-CoV 17 years after infection. While antibodies block infection when present, T cells are vital for long-term immune memory. We are excited to begin this controlled, randomized trial of boosting a previously administered DNA-based viral vector vaccine with our own Ad5 dual-antigen S plus N vaccine to see if it can augment protection in participants who have received the S-based vaccine alone,” added Dr Soon-Shiong.

Source: BusinessWire

Categories : Cardiovascular Disease Metabolic DisordersTags :

Are Lower Haemoglobin Levels Protective?

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Credit: Wikimedia CC0

A new study challenges the view that high haemoglobin levels are always desirable for health. 

A study based on two large human cohorts as well as experimental work supported the idea that lower haemoglobin levels may protect against both obesity and metabolic syndrome. The phenomenon may be related to the body’s adaptive response to low-oxygen conditions, which is exploited by endurance athletes in high-altitude training.

Haemoglobin levels vary from one individual to another, with normal levels in Finnish population ranging from 117 to 155 grams per litre in females and 134 to 167 grams per litre in males.

A recent study showed that individual differences in haemoglobin levels are strongly associated with metabolic health in adulthood. The haemoglobin levels were associated with body mass index, glucose metabolism, blood lipids and blood pressure. Subjects with lower haemoglobin levels were healthier in terms of metabolic measures. The study examined haemoglobin values within the normal range.  

“We found a clear association between hemoglobin levels and key cardiovascular traits, and the associations became more pronounced as the subjects aged,” said principal investigators Professor Juha Auvinen, doctoral student Joona Tapio and postdoctoral researcher Ville Karhunen.  

The effect of lower haemoglobin observed in the study is related to a mild oxygen deficiency in the body and the corresponding hypoxia inducible factors (HIF) response which is activated as a result. The research team of Professor Peppi Karppinen is internationally known for its studies on this phenomenon. The finding reinforces the understanding of the central role that the HIF response has in regulating the body’s energy metabolism.

“Haemoglobin levels are a good measure of the body’s ability to carry oxygen. A mild lack of oxygen activates the HIF response, which makes the body’s energy metabolism less economical and thus may protect against obesity and unfavourable metabolism,” explained study leader Prof Karppinen.

Prof Karppinen’s team has already shown in previous research that activation of the hypoxia response protects mice from obesity, metabolic syndrome, fatty liver and atherosclerosis. This is the first study to show the link between oxygen deficiency and a wide range of metabolic health markers in humans as well.

“Although this study uses multiple methods to establish links between lower body oxygen levels and metabolic health, it is very challenging to establish causality for the observed associations in human data. However, combining evidence from different components of the study, the results support that hypoxia response may also play an important role in peoples’ metabolic health,”explained co-leader of the study Professor Marjo-Riitta Järvelin.

“We also already know that in people living high above sea level, low oxygen levels in the habitat cause long-term activation of the HIF response. These people are slimmer, and they have better sugar tolerance and a lower risk of cardiovascular death,” said Prof Karppinen.

The study was based on a large cohort of people born in Northern Finland in 1966, which followed the health of 12 000 people since birth. The results were also replicated in The Cardiovascular Risk in Young Finns Study cohort material, which covers more than 1800 individuals. 

“Although this study uses multiple methods to establish links between lower body oxygen levels and metabolic health, it is very challenging to establish causality for the observed associations in human data. However, combining evidence from different components of the study, the results support that hypoxia response may also play an important role in peoples’ metabolic health”, explained study co-leader Professor Marjo-Riitta Järvelin.

Professor Peppi Karppinen said, “We also already know that in people living high above sea level, low oxygen levels in the habitat cause long-term activation of the HIF response. These people are slimmer, and they have better sugar tolerance and a lower risk of cardiovascular death.”

A question for future research is how to reduce the body’s oxidation levels if needed. This would be to achieve a permanent low-level activation of the HIF response and thus obesity protection. According to Prof Karppinen, the HIF enzymes that prompt a hypoxic response could potentially be used as targets of obesity and metabolism drugs in humans. Currently they are being used in Asia to treat renal anaemia.

Source: University of Oulu

Journal information: Auvinen, J., et al. (2021) Systematic evaluation of the association between hemoglobin levels and metabolic profile implicates beneficial effects of hypoxia. Science Advances. doi.org/10.1126/sciadv.abi4822.